PURPOSE: To prevent the display of a character wheel from being intentionally altered by forming a weld zone by welding one part of a contact part between a frame and a synthetic resin casing by using an ultrasonic welding means.

CONSTITUTION: A driving source for operating a count display means provided with a character wheel 2 is integrated into a frame 1, and this frame 1 is attached to the casing 5 from the opening part side of the casing 5. Then, the weld zone 6 provided with a through hole 60 to be welded by impressing ultrasonic waves from the outside of the casing 5 is formed at the position corresponding to the almost center of a front top plate 10a of the frame 1. Thus, the casing 5 can not be detached from the frame 1, and the display of the character wheel 2 is prevented from being intentionally altered.