To provide electric power for operating an ordinary IC by extracting an induced power which exists in the environment.

A switch 91 configured, for example, with a CMOSFET, and a controller 92 configured with a microcontroller which dissipates a small amount of current, are provided between a diode 3 and a capacitor 5. The controller 92 controls the switch 91, by detecting voltage discharge by the capacitor 5 and also controls a charge current supplied to the capacitor 5. Since the impedance of power supply due to the field detected by an antenna 1 is very high, inductance is not required between the diode 3 and capacitor 5. Moreover, level of triangular ripple generated by the capacitor 5 can be controlled with the controller 92, and variation of load can also be controlled similar to an ordinary switching regulator.