According to an aspect, there is provided a teaching device on which portable terminal equipment is mounted, the teaching device being used to teach operation to a robot. The teaching device includes a case section including a mounting surface on which the portable terminal equipment is mounted. The case section includes a first member including a stop switch for stopping the operation of the robot and configured to restrict the portable terminal equipment's moving in a first direction extending along the mounting surface and a second member provided to be capable of moving in the first direction relatively to the first member and configured to restrict the portable terminal equipment's moving in an opposite direction of the first direction.