Disclosed is a litz wire coil that is configured by spirally winding a litz wire on one plane by a predetermined number of turns. The litz wire is configured by twisting together a plurality of enameled wires formed by baking an insulating film on a conducting body. Pressure shaping is performed such that the litz wire has a substantially rectangular shape in cross section, and the flatness ratio of the litz wire in cross section (long side/short side) is controlled at 1.10 to 1.60, preferably 1.20 to 1.40, more preferably 1.25 to 1.35.