To provide a structure for generating signals by operating and controlling a roller ball with the feet, which is an entertainment device for keeping the health of the body by the exercise of the feet, and an application apparatus.

On a base 100, a spherical recessed seat 101 for supporting the roller ball 102 and an arc shape structure 103 are provided. A power source 104 forms a battery, a super capacitor or other capacitors capable of change from city electricity of AC to DC or primary and secondary charge and discharge, and energy is supplied. A roller ball detecting and measuring device 105 detects and measures the movement state of the roller ball 102 and is capable of operating or controlling a main unit 106 or a display device 107 as needed. An auxiliary device 108 to be operated or controlled with the feet is constituted of a mechanical and electrical switch unit and a solid-state electronic switch element.