To provide a forward/backward-moving changeover device for transmission, which can lower the sliding resistance of a forward clutch in reversing operation, enhance the fuel consumption, and reduce loss in the drive force.

The sun gear 11 of a planetary gear 10 is coupled with an output shaft 3, and a reverse brake 30 is interposed between a planet carrier 14 and a casing 4, and a ring gear 12 is coupled with an input shaft 2, while a forward clutch 20 is installed between the planet carrier 14 and ring gear 12. In reversing, the inner plate 23 of the forward clutch 20 is supported by the planet carrier 14 fixed to the casing 4 and hindered from rotating, so that the relative rotation between the inner plate 23 and outer plate 24 decreases to cause a reduction of the sliding resistance, which leads to enhancement of the fuel consumption and reduction of loss in the drive force.