PURPOSE: To enable a rotary bezel to rotate in both positive and negative directions or one direction and surely prevent the rotation due to erroneous operation by providing a part for regulating the rotation to one direction because of coupling with a rough part and a part for relieving the coupling with the rough part.

CONSTITUTION: When the opening 25 of the second rotary bezel 22 is not on the opposit side of a hook blade 11 of a plate spring 10, the first rotary bezel 21 can rotate in positive and negative directions. When the opening 25 is located on the hook blade 11 by turning the bezel 22, the hook 11 stands up and its tip couples with the rough part 23 on the bezel 21 and regulates the rotation of the bezel 21 in the opposite direction. If the bezel 21 is rotated from this state, the hook 11 is fell down to leave from the coupling state and the bezel 21 becomes possible to rotate in both positive and negative directions. Therefore, by adjusting the rotation operation of the bezel 22, one of regulations of one directional rotation, bidirectional rotation and unavailable rotation state can be selected, which makes the use convinient and erroneous operation preventable.