A power supply apparatus includes a main body, a first power connecting part and a foldable electrical connector. The main body includes a power converting circuit therein and has a first socket at a first side thereof. The first power connecting part has an end connected to the main body. The foldable electrical connector includes a housing and at least a conductive pin. The housing includes a connecting member and a receiving portion. The connecting member is electrically connected to the first socket of the main body. The conductive pin is disposed in the receiving portion and multi-angularly rotatable with respect to the housing so as to be selectively stored in the receiving portion or protruded from the housing.