Power transmission device

A power transmission device used to transmit a power in a wireless manner with another power transmission device, the power transmission device comprising:

• a coil that transmits or receives the power in a wireless manner, the coil having an annular shape;
• a shield member disposed on a side opposite to a side of the another power transmission device with respect to the coil in a power transmission direction;
• and
• an annular magnetic member provided between the coil and the shield member,
• wherein the shield member at least partially overlaps the coil when viewed in the power transmission direction, and an inner periphery of the shield member is located outside a position inside by a length four times a gap between the coil and the shield member from an inner periphery located inside among an inner periphery of the coil and an inner periphery of the magnetic member when viewed in the power transmission direction.