A hydraulic control device (12, 112, 212) for an automatic transmission (10, 110), the hydraulic control device (12, 112, 212) utilized for the automatic transmission (10, 110) including an input shaft drivably coupled to a drive source of a vehicle; a driving shaft drivably coupled to wheels; a synchronization mechanism switchable between a first mode, in which the synchronization mechanism is brought into an engaged state to connect the input shaft and the driving shaft to each other through a first power transfer path for rotation transfer, and a second mode, in which the synchronization mechanism is brought into a disengaged state to connect the input shaft and the driving shaft to each other through a second power transfer path for rotation transfer; and an engagement element (B1, C1, C2) provided at at least one location in the first power transfer path that couples the input shaft and the driving shaft to each other via the synchronization mechanism and the second power transfer path that couples the input shaft and the driving shaft to each other at least partially through a path that is different from the first power transfer path, and the hydraulic control device which is capable of supplying and discharging an engagement pressure (PLPM2) to and from the synchronization mechanism and the engagement element (B1, C1, C2), comprising: a first solenoid valve capable of supplying the engagement pressure; a source pressure generation section capable of generating a source pressure (PLPM2) at all times when the drive source is driven; a switching valve capable of supplying the engagement pressure, which is supplied from the first solenoid valve, switchably to one of the synchronization mechanism and the engagement element (B1, C1, C2), and switching whether supply of the source pressure, which is supplied from the source pressure generation section, to the synchronization mechanism as the engagement pressure is allowed or blocked; and a signal pressure supply section capable of supplying a signal pressure (PSLP) for switching the switching valve, wherein the engagement pressure which is supplied from the first solenoid valve is supplied to the synchronization mechanism in the case where the signal pressure is not supplied to the switching valve, and the engagement pressure which is supplied from the first solenoid valve is supplied to the engagement element (B1, C1, C2) and the source pressure is supplied to the synchronization mechanism as the engagement pressure in the case where the signal pressure is supplied to the switching valve. a driving shaft drivably coupled to wheels; a synchronization mechanism switchable between a first mode, in which the synchronization mechanism is brought into an engaged state to connect the input shaft and the driving shaft to each other through a first power transfer path for rotation transfer, and a second mode, in which the synchronization mechanism is brought into a disengaged state to connect the input shaft and the driving shaft to each other through a second power transfer path for rotation transfer; and an engagement element (B1, C1, C2) provided at at least one location in the first power transfer path that couples the input shaft and the driving shaft to each other via the synchronization mechanism and the second power transfer path that couples the input shaft and the driving shaft to each other at least partially through a path that is different from the first power transfer path, and a first solenoid valve capable of supplying the engagement pressure; a source pressure generation section capable of generating a source pressure (PLPM2) at all times when the drive source is driven; a switching valve capable of supplying the engagement pressure, which is supplied from the first solenoid valve, switchably to one of the synchronization mechanism and the engagement element (B1, C1, C2), and switching whether supply of the source pressure, which is supplied from the source pressure generation section, to the synchronization mechanism as the engagement pressure is allowed or blocked; and a signal pressure supply section capable of supplying a signal pressure (PSLP) for switching the switching valve, wherein the engagement pressure which is supplied from the first solenoid valve is supplied to the synchronization mechanism in the case where the signal pressure is not supplied to the switching valve, and the engagement pressure which is supplied from the first solenoid valve is supplied to the engagement element (B1, C1, C2) and the source pressure is supplied to the synchronization mechanism as the engagement pressure in the case where the signal pressure is supplied to the switching valve.