In a power transmitting device, a discharge port (104) of an electromagnetic pump (100) is connected through a switching valve (50) to an oil path (48) connecting to a clutch (C1) for vehicle starting and to an oil path (44) connecting to a signal pressure input port (62a) of a regulator valve (60). This enables that, while an engine (12) is being operated, an operating oil as a signal pressure to the regulator valve (60) can be supplied thereto by driving the electromagnetic pump (100) and, while the engine (12) is in an automatically stopped state, hydraulic pressure can be supplied to the clutch (C1) by driving the electromagnetic pump (100). The configuration enables the device to be made smaller than devices having a configuration provided with both a pressure regulating valve for driving the regulator valve (60) and an electromagnetic pump for supplying hydraulic pressure to the clutch (C1) while the engine (12) is being automatically stopped.