diff --git a/optuna_dashboard/_app.py b/optuna_dashboard/_app.py
index 731de524..87efaae5 100644
--- a/optuna_dashboard/_app.py
+++ b/optuna_dashboard/_app.py
@@ -221,10 +221,8 @@ def create_app(
         ) = get_cached_extra_study_property(study_id, trials)
 
         plotly_graph_objects = get_plotly_graph_objects(system_attrs)
-        trials_id2number = {trial._trial_id: trial.number for trial in trials}
-        skipped_trials = [
-            trials_id2number[trial_id] for trial_id in get_skipped_trial_ids(system_attrs)
-        ]
+        skipped_trial_ids = get_skipped_trial_ids(system_attrs)
+        skipped_trials = [t.number for t in trials if t._trial_id in skipped_trial_ids]
         return serialize_study_detail(
             summary,
             best_trials,
diff --git a/optuna_dashboard/_serializer.py b/optuna_dashboard/_serializer.py
index d3cd786f..af3ed242 100644
--- a/optuna_dashboard/_serializer.py
+++ b/optuna_dashboard/_serializer.py
@@ -167,7 +167,7 @@ def serialize_study_detail(
     if serialized["is_preferential"]:
         serialized["preference_history"] = serialize_preference_history(system_attrs)
         serialized["preferences"] = get_preferences(system_attrs)
-        serialized["skipped_trials"] = skipped_trials
+        serialized["skipped_trial_numbers"] = skipped_trials
     serialized["plotly_graph_objects"] = [
         {"id": id_, "graph_object": graph_object}
         for id_, graph_object in plotly_graph_objects.items()
diff --git a/optuna_dashboard/ts/apiClient.ts b/optuna_dashboard/ts/apiClient.ts
index abfe057a..9f9cd8cb 100644
--- a/optuna_dashboard/ts/apiClient.ts
+++ b/optuna_dashboard/ts/apiClient.ts
@@ -99,7 +99,7 @@ interface StudyDetailResponse {
   preferences?: [number, number][]
   preference_history?: PreferenceHistoryResponce[]
   plotly_graph_objects: PlotlyGraphObject[]
-  skipped_trials?: number[]
+  skipped_trial_numbers?: number[]
 }
 
 export const getStudyDetailAPI = (
@@ -140,7 +140,7 @@ export const getStudyDetailAPI = (
           convertPreferenceHistory
         ),
         plotly_graph_objects: res.data.plotly_graph_objects,
-        skipped_trials: res.data.skipped_trials ?? [],
+        skipped_trial_numbers: res.data.skipped_trial_numbers ?? [],
       }
     })
 }
diff --git a/optuna_dashboard/ts/components/PreferentialTrials.tsx b/optuna_dashboard/ts/components/PreferentialTrials.tsx
index 26cc4976..5fc0ac32 100644
--- a/optuna_dashboard/ts/components/PreferentialTrials.tsx
+++ b/optuna_dashboard/ts/components/PreferentialTrials.tsx
@@ -198,7 +198,7 @@ export const PreferentialTrials: FC<{ studyDetail: StudyDetail | null }> = ({
     studyDetail.preference_history
       ?.filter((h) => !h.is_removed)
       .map((p) => p.clicked)
-      .concat(studyDetail.skipped_trials) ?? []
+      .concat(studyDetail.skipped_trial_numbers) ?? []
   )
   const activeTrials = studyDetail.trials.filter(
     (t) =>
diff --git a/optuna_dashboard/ts/types/index.d.ts b/optuna_dashboard/ts/types/index.d.ts
index 01868f7b..a51a88d9 100644
--- a/optuna_dashboard/ts/types/index.d.ts
+++ b/optuna_dashboard/ts/types/index.d.ts
@@ -206,7 +206,7 @@ type StudyDetail = {
   preferences?: [number, number][]
   preference_history?: PreferenceHistory[]
   plotly_graph_objects: PlotlyGraphObject[]
-  skipped_trials: number[]
+  skipped_trial_numbers: number[]
 }
 
 type StudyDetails = {