diff --git a/src/Functions/LowerUpperUTF8Impl.h b/src/Functions/LowerUpperUTF8Impl.h
index 7d60bd54d2f..f174bcd5f3e 100644
--- a/src/Functions/LowerUpperUTF8Impl.h
+++ b/src/Functions/LowerUpperUTF8Impl.h
@@ -6,6 +6,7 @@
 
 #    include <Columns/ColumnString.h>
 #    include <Functions/LowerUpperImpl.h>
+#    include <base/scope_guard.h>
 #    include <unicode/ucasemap.h>
 #    include <unicode/unistr.h>
 #    include <unicode/urename.h>
@@ -49,6 +50,11 @@ struct LowerUpperUTF8Impl
         if (U_FAILURE(error_code))
             throw DB::Exception(ErrorCodes::LOGICAL_ERROR, "Error calling ucasemap_open: {}", u_errorName(error_code));
 
+        SCOPE_EXIT(
+        {
+            ucasemap_close(case_map);
+        });
+
         size_t curr_offset = 0;
         for (size_t row_i = 0; row_i < input_rows_count; ++row_i)
         {