Provision of a portable apparatus which is of a simple construction and which can prevent a lock member arranged at a lock position where a pushbutton is locked from being erroneously rotated to an excessive degree. A pipe inserted into a through-hole of an apparatus exterior body is fixed to the apparatus exterior body. The pipe consists of a single component, and has a male screw portion and a stopper portion on an external arrangement tube portion thereof. A lock member is provided with a female screw portion, a lock part, and a lock portion configured to move toward and away from the stopper portion. The two screw portions and are threadedly engaged with each other, and the lock member is mounted so as to be movable in the axial direction of the pipe. A shaft portion of a pushbutton is passed through the pipe, and the pushbutton is urged toward the exterior of the apparatus exterior body by a spring. A head with which the pushbutton is equipped has an opposing portion facing the lock part. A retaining ring is mounted to a shaft end portion of the shaft portion situated inside the apparatus exterior body, and the pushbutton is prevented from being detached from the pipe.