To provide an injector driving device capable of injecting fuel into an engine, suppressing electromagnetic noise caused by switching operation of a DCDC converter, and reducing cost required by measures against electromagnetic noise.

This injector driving device 30 is provided with a charge capacitor 40 charged into higher voltage than power supply voltage as a peak current supply circuit and the DCDC converter 34 having a MOSFET 36 as a switching element and raising power supply voltage to charge the charge capacitor 40. A charging control part 50 in a control circuit 32 detects rise of injection signals S1a to S1d as injection timing and sets a switching manner of MOSFET 36 required in charging the charge capacitor 40 based on average period of injection timing.