The invention relates to a power generation device which comprises a first housing, a magnetic element, a second housing, an induction coil and a first piezoelectric element. The magnetic element is fixedly arranged on the first housing, the first housing and the second housing are clamped with each other to form a space, the magnetic element is arranged in the space, and the induction coil is fixedly arranged in the second housing and disposed around the magnetic element in the space. The first piezoelectric element is disposed between the magnetic element and the first housing. When the first housing and the second housing are stressed by external force, the first housing and the second housing perform relative motion, so that the induction coil inducts magnetic flux change to generate induction current, and meanwhile, the first piezoelectric element absorbs the pressure between the magnetic element and the second housing to generate a first charge. Green products without external electrical energy or batteries can be obtained by integrating other appropriate power consumption devices with the power generation device.