To provide a control device of a speed change gear which is improved in power transmission efficiency, and can control a speed change adapted to a requirement.

In the control device of the speed change gear which is arranged on each power transmission passage, and changes a change gear ratio by varying extrusion capacities of two pump motors which can alternately receive pressure fluids, the control device comprises a speed change control means (steps S13, S15 and S16) which sets the speed change ratio in one of modes of a first speed change mode for setting the speed change ratio by varying the extrusion capacity of the other pump motor with the extrusion capacity of one pump motor fixed, a second speed change mode for setting each extrusion capacity simultaneously in a mutual opposite direction, and a third speed change mode for setting each extrusion capacity simultaneously in the same direction, a travel determination means (step S12) which determines the traveling state of a vehicle, and a speed change mode selection means (steps S12, S14) which selects the speed change mode on the basis of the traveling state.