A power generating device is disclosed that includes a power generating unit, an inductor, a switch connected to the inductor in series, and a control circuit. The power generating unit includes a piezoelectric element, and upper and lower electrodes disposed on surfaces of the piezoelectric element. The inductor is electrically connected to the electrodes in parallel, with the inductor and a capacitance component constituting a resonance circuit. The control circuit has a driving mode in which it controls the switch to an ON state in synchronism with the voltage generated in the piezoelectric element becoming a peak value. Further, in a rest mode, the control circuit controls the switch to be in an OFF state when the voltage generated in the piezoelectric element has the peak value.