A power generating device and an application thereof relate to the technical field of micro power generating devices and resolve the technical issue of inconvenient powering of existing electronic products. The power generating device comprises a support board. A power generator, a coil spring mechanism, and a power wheel are disposed on the support board. The coil spring mechanism comprises a support shaft vertically connected to the support board. A driven gear, a coil spring, and a main drive gear are movably sleeved over the support shaft. One end of the coil spring is connected to the driven gear, and the other end of the coil spring is connected to the main drive gear. The main drive gear meshes and is in transmission connection with a spindle gear of the power generator. The driven gear is in transmission connection with the power wheel via a unidirectionally driven transmission gear. By synchronizing during the operation of an electronic product, the coil spring mechanism obtains energy. The energy of the coil spring mechanism is stored and released to the power generator, and the power generator coverts mechanical energy into electricity and outputs the same so as to charge the battery in the electronic product, meeting need for electricity for operation of the electronic product.