The invention relates to a transmission device applied to a power switch. The transmission device comprises an input shaft connected with a power source of the power switch to realize rotation between the first position and the second position; a single output shaft which is rotatably connected with a contact of the power switch; an energy storage spring connected with the input shaft and the output shaft, and a stop mechanism capable of selectively stopping rotation of the output shaft. In a rotation process of the input shaft between the first position and the second position in any direction, the stop mechanism stops rotation of the output shaft before the input shaft reaches a terminal point, the stop mechanism releases the output shaft after the input shaft reaches the terminal point, and the output shaft is driven by the energy storage spring to rotate in a direction same as the rotation direction of the input shaft. The invention further relates to the power switch equipped with the transmission device. The transmission device is advantaged in that switching of the double power switch can be realized through a single contact, and the structure is simple and compact.