A simply structured rattling noise reduction device for a vehicle capable of preventing rattling certainly under neutral position. The rattling noise reduction device is applied to a vehicle having a transmission mechanism configured to transmit a torque of a prime mover to an output member through a mating transmission mechanism, and a shifting means capable of selecting a drive position in which the torque of the prime mover is transmitted to the output member and a neutral position in which the torque of the prime mover is not transmitted to the output member, and in which the transmission mechanism is configured to idle any one of rotary members thereof to prevent the torque from being applied to the output member in case the neutral position is selected. The rattling noise reduction device comprises a slidable contact means, which is contacted frictionally with the output member, or with a rotary member and transmitting the torque to the output member, or with a member integrated with the rotary member and, in case the neutral position is selected by operating the shifting means.