To provide a transmission quickly shifting by shortening the select operation time.

This transmission includes a select shift gear 72 fitted into a shift shaft 50 movable and rotatable in the select direction and formed with a spline groove. The shift shaft 50 is structured by coaxially arranging a plurality of cylindrical members 61a-61d, and each one end of the plurality of cylindrical members 61a-61d is formed with arms 65a-65d, and the other end thereof is formed with a spline groove to be engaged with engagement teeth of the select shift gear 72. The select shift gear 72 is moved in the select direction to select a predetermined cylindrical member 61a-61d, and rotated to be engaged with the cylindrical members 61a-61d to selectively rotate the cylindrical members 61a-61d to move the arms 65a-65d in the shift direction.