A droplet ejection apparatus includes a main power supply, power cutoff detecting means, a standby power supply, residual vibration detecting means, storage means, and ejection failure detecting means. When cutoff of the main power supply is detected, an actuator is driven by a driving circuit, the residual vibration detecting means detects the residual vibration of the diaphragm displaced by the driving of the actuator, and the storage means stores the vibration pattern of the residual vibration of the diaphragm detected by the residual vibration detecting means and/or the information obtained from the vibration pattern. The ejection failure detecting means include an oscillation circuit that oscillates in response to an electric capacitance component that varies with the residual vibration of the diaphragm.