A transmission apparatus is capable of retaining an endless transmission chain on a rotatable member, even where a small inter-axis distance remains between two rotatable shafts to which each of two rotatable members is drivingly connected. The transmission includes a drive sprocket member for connecting to a main drive shaft. The transmission also includes a driven sprocket member, connected to the output shaft in parallel with the main drive shaft and including a plurality of transmission sprockets. The transmission further includes a chain interconnecting both sprocket members, and a transmission shift mechanism for positioning the chain among the transmission sprockets. The drive sprocket member is supported at the main drive shaft in the rotary center line direction, in such a way that the chain is applied to both sprocket members in parallel with a plane crossing at a right angle with the rotary center line of the main drive shaft.