An endoscopic apparatus includes an ultrasonic vibrator, a diffraction grating, an electrical energy generator, a detector, a determination unit, a controller. The diffraction grating converts the ultrasonic vibration into a surface acoustic wave propagating on a surface of the transparent member. The detector detects reflected electrical energy reflected from the energy supply system. The determination unit determines whether the electrical energy suitable to drive the ultrasonic vibrator has been supplied to the ultrasonic vibrator based on the reflected electrical energy detected by the detector. The controller controls the electrical energy output from the signal generator based on a determination result of the determination unit.