A piezoelectric element driving circuit includes: a transformer; a switch circuit; a reactance element connected in parallel with the piezoelectric element on one of the primary side and the secondary side of the transformer, the reactance element forming a resonant circuit that performs parallel resonance at the driving frequency with a capacitance component in an equivalent circuit of the piezoelectric element and an inductance component of the transformer; a pulse generating circuit for generating a driving pulse for the switch circuit; and a duty ratio controlling circuit for being supplied with the driving pulse, limiting a duty ratio of the driving pulse such that a value of the driving voltage falls within a range equal to or lower than the specification voltage value on the load side, and outputting the driving pulse whose duty ratio is limited to the switch circuit.