A wireless power transmission device comprises a transmitting coil assembly and a receiving coil assembly. The transmitting coil assembly includes a first magnetic core and a transmitting coil winding. The first magnetic core has a substantial U-shaped body portion, a first pillar portion disposed at a first end of the U-shaped body portion, and a second pillar portion disposed at a second end of the U-shaped body portion. The transmitting coil winding has a first transmitting coil winding wound around the first pillar portion and a second transmitting coil winding wound around the second pillar portion. The receiving coil assembly is interposed between the first pillar portion and the second pillar portion and electromagnetically coupled therewith. The receiving coil assembly includes a second magnetic core and a receiving coil winding.