To provide a power generation device that increases the power of an oscillator 43 by increasing the mass of the oscillator 43 and can make a metal weight 53 less likely to come off.

The power generation device includes: a frame 1; an oscillator 2 provided on the inside of the frame 1; a deflection portion 3 that connects between the frame 1 and the oscillator 2 and undergoes a deflection when the oscillator 2 is displaced; and a power generating unit 7 that consists of a bottom electrode 4, a piezoelectric layer 5, and a top electrode 6 stacked in order from the bottom to top on the deflection portion 3 and generates AC voltage in compliance with the swing of the oscillator 2. The oscillator 2 includes a silicon weight 8a formed of silicon and the metal weight 8b formed on one surface of the silicon weight 8a, and is also provided with a through-hole 9 that penetrates through both sides of the silicon weight 8a, at a position where the metal weight 8b is disposed. A drop-out preventing portion 10 is formed that protrudes as an integral body from the metal weight 8b to the other surface of the oscillator 2 through the through-hole 9 in such a shape as to be caught on the peripheral edge of the through-hole 9.