Provided are a feed unit, a feed system, and an electronic device that enable transmission efficiency control according to the position of a device when electric power transmission using a magnetic field is performed between devices. The feed unit includes a power transmission section including a power transmission coil configured to perform electric power transmission using a magnetic field, and an auxiliary resonance section including one or a plurality of resonators. The resonator includes an auxiliary coil wound to form a gap in at least a partial region.