To provide a toroidal transformer, obtained by extremely conveniently and quickly executing fixing, alignment, welding and connection of the tip and rear end of a winding and assembling and coating of an insulating cover, in manufacturing processes such as coil winding and welding.

In this toroidal transformer, constituted of protectively coated periphery of a core with a core insulating cover 3, winding a primary coil around the cover 3, protectively coated periphery of the primary coil with a coil insulating cover 5, having a secondary coil wound around the cover 5 and the tips and rear ends of the primary and secondary coils are drawn out to the external of a housing 7 so as to be respectively connected to taps, two or more winding end part winding pins are erected and fixed at prescribed points of the upper end face of the cover 3, the tip and rear end of the primary coil are wound around the winding pins, two or more winding end part winding pins are erected and fixed on prescribed points on the upper surface of the cover 5 at a prescribed interval, and the tip and rear end of the secondary coil are respectively wound around the pins.