A contactless power transfer transformer includes main body. The main body includes magnetic pole core members, winding wire core member, and wire. The winding wire core member is orthogonal to the magnetic pole core members and connects one portion of each of the pair of parallel magnetic pole core members with each other. The main body is fixed to fixing plate having a magnetic shield function and heat dissipation function. The connecting position of the winding wire core member with respect to the magnetic pole core members is located toward one side from a center in the longitudinal direction of the magnetic pole core members. At least a space between the pair of the magnetic coil core members each containing an end portion longer in distance to the connecting position is used as an arrangement space of component electrically connected to the electric wire.