A wireless power transfer system includes: a primary coil support member provided with a fitting member that is fit with a fit member, the primary coil support member being configured to support the power supply primary coil; a secondary coil support member provided with the fit member with which the fitting member is fit, the secondary coil support member being configured to support the power supply secondary coil; and a posture/position adjustment mechanism capable of adjusting a relative posture or position between the primary coil support member and the secondary coil support member to change the posture between a releasing posture and a fitting posture. When the relative posture is changed from the releasing posture to the fitting posture by the adjustment of the posture/position adjustment mechanism, the power supply apparatus performs wireless power transfer from the power supply primary coil to the power supply secondary coil.