To make the whole circuit scale into a small size.

The piezoelectric transformer drive device, driving a piezoelectric transformer 14 with a driving voltage output from a drive circuit 12 according to an input voltage and operating the piezoelectric transformer 14 at a resonance frequency when a phase difference between an electric current run by the driving and the driving voltage becomes zero, includes a current detection circuit 13 that detects an electric current running through the piezoelectric transformer 14 and converts the current into a voltage, and a phase shift circuit 17 that inputs, into a driving voltage, a voltage obtained by shifting a phase of a voltage at which the detection current by the current detection circuit 13 is converted, by a predetermined phase shifting amount.