To reduce manufacturing cost, and to facilitate locking operation, without lowering functionality such as waterproofness, in a portable electronic device.

This device is equipped with a case body 15, a winding crown 25, a first push button 26 and a second push button 27 as external operation members arranged on the outer peripheral part of the case body 15, and a rotary bezel 30 supported slidably on the case body 15 and putting the winding crown 25, the first push button 26 and the second push button 27 into the operation prohibiting state approximately simultaneously by being slid.