To improve reliability of a power supply apparatus having a good fitting workability of an external device to terminal pins, by restricting a prying force against a tip opening, which is generated when engaging a socket terminal of a starting system to terminal pins of an external device.

In a power supply apparatus 13, in which an overload protection system 3 and a starting system 4 are coupled, and the device using it, a socket terminal 5 is connected to the electrical parts of the overload protection system 3, and a convex part 10c, which is apposed to the tip opening 5a of the socket terminal 5 and nearly matches with a shape of the tip opening 5a, and which has a little gap, is comprised.