Provided is a variable speed transmission device for a tractor, the device having a narrow vertical width or horizontal width, and having a short longitudinal length. A variable speed output unit (23)is present further to a rearward side of a vehicle body than a compound planetary transmission unit (22). A planetary unit output axis center (22Y) and a variable speed unit input axis center (23X) have the same axis center. A motive power transmission unit (24) from an engine (6) to a continuously variable transmission unit (21) and the compound planetary transmission unit (22) is provided witha rotation transmission shaft (80) connected in a coordinated manner to an output shaft (6a) of the engine (6) and extending along the longitudinal direction of the vehicle body, a pump transmission unit (85) that inputs motive power from the rotation transmission shaft (80) into the continuously variable transmission unit (21), and a planetary transmission unit (81) that inputs motive power fromthe rotation transmission shaft (80) into the compound planetary transmission unit (22). The rotation transmission shaft (80) is located further to the rearward side of the vehicle body than the engine (6), and is parallel with respect to a motor shaft (50a) and a pump shaft (51a). The continuously variable transmission unit (21) and both the compound planetary transmission unit (22) and the variable speed output unit (23) are present in the same place in the longitudinal direction of the vehicle body.