To miniaturize a transmission by eliminating a driving gear and driven gear dedicated to reverse and shortening an axial length of the transmission.

The gear transmission has an input shaft 11 inputted with engine power, and an output shaft 12 with a plurality of transmission gear trains 21-26 provided between it and the input shaft 11 to output changed power. The driven gear 35 meshing with an output gear 35 fixed to the output shaft 12 is provided on a drive shaft 16, and an engagement clutch 39 for changing between a state of connecting the driven gear 35 and a driven gear 21b for transmission forming the transmission gear train 21, and a state of releasing connection is provided on a reverse shaft 36. A first reverse idler gear 37 meshing with the driven gear 21b, and a second reverse idler gear 38 meshing with the driven gear 35 are provided on the reverse shaft 36.