The object is to simplify the construction of a speed change apparatus in which an engine drive force is speed-changed in a plurality of speed ranges and speed-changed steplessly in each speed range, with using a stepless speed change device (10), planetary transmission mechanisms (P1, P2, P3) and clutches (C1, C2).There is provided a main speed change device (B) configured to combine an output from the stepless speed change device (10) and the drive force from the engine trough the first, second and third planetary transmission mechanisms (P1, P2, P3) and then output the resultant combined force from an output shaft (41). There is provided an auxiliary speed change device (20) for effecting speed change on the drive force from the output shaft (41) of the main speed change device (B) and then outputting the speed-changed force.