To provide a step-up transformer that can prevent cutting of windings.

This step-up transformer is provided with a base member, primary and secondary windings disposed on the base member, and a pair of magnetic core members which are disposed to face each other in the vertical direction around the primary and secondary windings and form a closed magnetic path. In this transformer, a hollow cylindrical wall section forming a winding shaft section is erected on the central part of the surface of the base member and a step section, which is connected to the lower end section of the cylindrical wall section and made higher than the surface of the base member is formed. In addition, a gap section is formed from the first end section of the base member to the corresponding hollow cylindrical wall section, and a first recessed section is formed on the first side wall section of the side wall section of the recessed section, which is in contact with the base section of the cylindrical wall section. Moreover, a second recessed section is formed on the second sidewall section of the gap section, facing the first sidewall section at a position separated from the cylindrical wall section and winding connecting terminals are provided in the first end section of the base member.

COPYRIGHT: (C)2004,JPO