According to one embodiment, a wireless power transfer system performs electrical power transfer and signal communication by magnetic field resonance. A power transfer apparatus includes a first resonator configured to resonate at a predetermined frequency and to switch a Q-factor between high and low, and a first controller configured to set the Q-factor of the first resonator high in the electrical power transfer, and to set the Q-factor of the first resonator low in the signal communication. The power reception apparatus includes a second resonator configured to resonate at the predetermined frequency and to switch a Q-factor between high and low, and a second controller configured to set the Q-factor of the second resonator high when performing the electrical power transfer and to set the Q-factor of the second resonator low when performing the signal communication.