diff --git a/app/assets/stylesheets/tasks.scss b/app/assets/stylesheets/tasks.scss
index 73efd615..165d744e 100644
--- a/app/assets/stylesheets/tasks.scss
+++ b/app/assets/stylesheets/tasks.scss
@@ -40,6 +40,7 @@
 
 .task-card {
   margin: 0;
+  transition: opacity 0.3s ease;
 }
 
 .task-state-btn i {
diff --git a/app/controllers/tasks_controller.rb b/app/controllers/tasks_controller.rb
index cc71570e..68cc1243 100644
--- a/app/controllers/tasks_controller.rb
+++ b/app/controllers/tasks_controller.rb
@@ -75,6 +75,13 @@ def update
     end
 
     respond_to do |format|
+      format.turbo_stream do
+        if turbo_frame_request?
+          render :update
+        else
+          redirect_to @task, notice: "タスクを更新しました．"
+        end
+      end
       format.html { redirect_to @task, notice: "タスクを更新しました．" }
       format.json { render :show, status: :ok, location: @task }
     end
@@ -82,15 +89,29 @@ def update
     flash.now[:danger] = 'このタスクは他のユーザーによって更新されました．'
     get_form_data
     respond_to do |format|
+      format.turbo_stream do
+        if turbo_frame_request?
+          render turbo_stream: turbo_stream.replace("task_card_#{@task.id}", partial: "tasks/task", locals: { task: @task }), status: :conflict
+        else
+          render :edit, status: :conflict
+        end
+      end
       format.html { render :edit, status: :conflict }
-      format.json { render json: { error: flash[:error] }, status: :conflict }
+      format.json { render json: { error: flash.now[:danger] }, status: :conflict }
     end
   rescue
     flash.now[:danger] = 'タスクの更新に失敗しました．'
     get_form_data
     respond_to do |format|
+      format.turbo_stream do
+        if turbo_frame_request?
+          render turbo_stream: turbo_stream.replace("task_card_#{@task.id}", partial: "tasks/task", locals: { task: @task }), status: :unprocessable_entity
+        else
+          render :edit, status: :unprocessable_entity
+        end
+      end
       format.html { render :edit, status: :unprocessable_entity }
-      format.json { render json: @document.errors, status: :unprocessable_entity }
+      format.json { render json: @task.errors, status: :unprocessable_entity }
     end
   end
 
diff --git a/app/views/tasks/_task.html.erb b/app/views/tasks/_task.html.erb
index 1b8fb68a..3755230b 100644
--- a/app/views/tasks/_task.html.erb
+++ b/app/views/tasks/_task.html.erb
@@ -1,24 +1,24 @@
-<div class="card h-100 task-card <%= 'opacity-50' if task.completed? %>">
+<div id="task_card_<%= task.id %>" class="card h-100 task-card <%= 'opacity-50' if task.completed? %>">
   <div class="card-body d-flex flex-column">
     <div class="d-flex justify-content-between align-items-center mb-3 gap-2">
-      <%= turbo_frame_tag "task_#{task.id}" do %>
+      <%= turbo_frame_tag "task_state_btn_#{task.id}" do %>
         <% if task.completed? %>
           <%= button_to task, method: :patch, params: { task: { task_state_id: TaskState.todo.id } }, class: "btn btn-link p-0 border-0 task-state-btn" do %>
             <i class="far fa-check-circle" style="color: <%= task.state.color %>;"></i>
           <% end %>
         <% else %>
-          <%= button_to task, method: :patch, params: { task: { task_state_id: TaskState.todo.id } }, class: "btn btn-link p-0 border-0 task-state-btn" do %>
+          <%= button_to task, method: :patch, params: { task: { task_state_id: TaskState.done.id } }, class: "btn btn-link p-0 border-0 task-state-btn" do %>
             <i class="far fa-dot-circle" style="color: <%= task.state.color %>;"></i>
           <% end %>
         <% end %>
       <% end %>
-        <% unless task.completed? %>
-          <% if task.overdue? %>
-            <p class="task-deadline task-deadline-overdue">期限切れです！</p>
-          <% else %>
-            <p class="task-deadline task-deadline-ongoing"><%= days_to_deadline_as_string task %></p>
-          <% end %>
+      <% unless task.completed? %>
+        <% if task.overdue? %>
+          <p class="task-deadline task-deadline-overdue">期限切れです！</p>
+        <% else %>
+          <p class="task-deadline task-deadline-ongoing"><%= days_to_deadline_as_string task %></p>
         <% end %>
+      <% end %>
       <small class="text-muted task-creator-badge">
         <i class="bi bi-person-fill"></i>
         <%= link_to task.assigner.name, task.assigner, class: "text-muted text-decoration-none" %>
diff --git a/app/views/tasks/update.turbo_stream.erb b/app/views/tasks/update.turbo_stream.erb
new file mode 100644
index 00000000..248990bb
--- /dev/null
+++ b/app/views/tasks/update.turbo_stream.erb
@@ -0,0 +1,3 @@
+<%= turbo_stream.replace "task_card_#{@task.id}" do %>
+  <%= render partial: "task", locals: { task: @task } %>
+<% end %>