To supply a hydraulic fluid to a hydraulic load, while adjusting a speed-change ratio, by using a speed-change pump for changing the speed-change ratio, by moving the hydraulic fluid between a primary pulley and a secondary pulley.

This driving device is provided with a suction oil passage 67 for connecting a reservoir 52 to a suction side port 64a of a switching valve 64 via a check valve 65 and a delivery side oil passage 68 for connecting a delivery side port 64b of the switching valve 64 to the hydraulic load via a check valve 70. The check valve 65 allows a flow of the hydraulic fluid to the suction side port 64a from the reservoir 52, and cuts off the flow of the hydraulic fluid to the reservoir 52 from the suction side port 64a. The check valve 70 allows a flow of the hydraulic fluid to the hydraulic load from the delivery side port 64b, and cuts off the flow of the hydraulic fluid to the delivery side port 64b from the hydraulic load. A speed-change hydraulic pump 60 sucks the hydraulic fluid of the reservoir 52 via the check valve 65, and can deliver and supply this sucked hydraulic fluid to the hydraulic load via the check valve 70.

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