PURPOSE: To easily execute the training of a biofeedback in a routine way with a play feeling by visually controlling the operation of the mobile device (part) of a toy based on a bio-signal detected with a bio-signal sensor in the toy to utilize a biofeedback device.

CONSTITUTION: A brain wave detected with a brain wave sensor 1 is amplified by an amplifier 4 and inputted to a band-pass filter 5. For example, only an alpha wave to appear at the time of an emotional stableness is made to pass to a control part 6. By such a control part (b), only when the voltage level of the inputted signal is at a certain value or above, a current flowing is executed to a heating element 3 in a mobile device 2. In such a constitution, by the bio-signal generated from one's own body, new discover and joy to move the toy can be sensed, and simultaneously, an emotional quiet degree can be recognized by the movement of the mobile part of the toy.