To provide a transformer equipped with a bobbin in which coils can be regularly wound, and the winding height of the coils can be made low.

A coil 2 is wound around a winding groove part 5 of a bobbin 1. The lead lines 3 of the coil 2 are wound around output terminals 6 provided so as to be erected on the edge face of the bobbin 1 so as to be connected. Ribs 4 for leading the lead lines 3 of the coil 2 are formed at the winding groove part 5. The projection and recession of the ribs 4 is used so that each lead line 3 can be hung from the ribs 4 so as to be led. The position of each rib 4 is arranged so that the lead lines 3 cannot be overlapped.