diff --git a/app/src/main/java/univ/earthbreaker/namu/feature/book/BookDialog.kt b/app/src/main/java/univ/earthbreaker/namu/feature/book/BookDialog.kt
index 1dee869..8b35092 100644
--- a/app/src/main/java/univ/earthbreaker/namu/feature/book/BookDialog.kt
+++ b/app/src/main/java/univ/earthbreaker/namu/feature/book/BookDialog.kt
@@ -67,7 +67,7 @@ fun BookDialog(
             LazyColumn(modifier = Modifier.fillMaxHeight(0.7f)) {
                 items(bookInfo.categories) {
                     CharacterTypeItem(
-                        characterCategory = it.characterType.type,
+                        characterCategory = it.characterType.type ?: "",
                         characters = it.characters,
                         acquiredCount = it.acquiredCount,
                     )