There is provided a hydraulic control device for an automatic transmission, which is comprised of an engagement state determining section and a protection control section. If the engagement state determining section determines that each clutch, which is supplied with a line pressure via a regulating valve having a spool and has an oil pressure switch disposed in an oil channel, is held in an engaged state when gears are not changed, the protection control section sets a command pressure for the regulating valve to a protective oil pressure lower than the line pressure. This brings the regulating valve into a pressure-regulating state to cause lands of the spool to form apertures that reduce hydraulic vibration applied to the line pressure. This inhibits an oil pressure beyond an acceptable value from being applied to the oil pressure switch, and therefore improves the durability of the oil pressure switch.