A C-shaped fixed core is provided at a power receiving portion, and a secondary coil is wound on a vertical portion of the fixed core. A moving core is vertically movable in sliding contact with distal end surfaces of horizontal portions of the fixed core. A primary coil, having an air core portion, is provided at a charging coupler. When the charging coupler is attached to the power receiving portion, the moving core is moved downward to extend through the air core portion of the primary coil, and opposite end portions of the moving core are contacted respectively with the horizontal portions of the fixed core. As a result, a magnetic circuit is formed between the primary and secondary coils. The charging coupler is lightweight since it does not have a core.