PROBLEM TO BE SOLVED: To provide an oscillator, a rectifier and a transceiver capable of being miniaturized.SOLUTION: An oscillator 100 comprises: an oscillation part 101 having a variable oscillatory frequency by a magnetic field; and conductors 103a, 103b connected to the oscillation part. The oscillation part 101 and conductors 103a, 103b are arranged so that the current flowing into the conductors is higher than that flowing into the oscillation part and a magnetic field generated by the current flowing into the conductors, is applied to the oscillation part.