A fluid pressure control device disposed between a fluid supply source and a fluid actuator comprising: an inlet port connected to the fluid supply source; an outlet port connected to the fluid actuator; a supply valve configured to adjust an area of a flow path connecting the inlet port and the outlet port; and a diaphragm configured to displace a valve element of the supply valve, wherein a pilot chamber is formed on one side of the diaphragm, a feedback chamber communicating with the outlet port is formed on another side of the diaphragm, a pilot pressure supply solenoid valve is disposed in a flow path connecting the inlet port and the pilot chamber, and a pilot pressure discharge solenoid valve is disposed in a flow path through which a pressure fluid in the pilot chamber is discharged to an exterior, and wherein the fluid pressure control device further comprises a control unit configured to control the pilot pressure supply solenoid valve and the pilot pressure discharge solenoid valve, characterized in that the fluid pressure control device is configured to transition from a normal mode, in which a fluid pressure supplied to the fluid actuator is set to an operating pressure, to a standby mode, in which the fluid pressure is set to a standby pressure that is lower than the operating pressure, wherein a transition from the normal mode to the standby mode is performed automatically on the condition that a flow rate flowing toward the fluid actuator continuously falls below a predetermined value for a predetermined time period or the transition is performed manually on the condition that a mode switching signal input from the exterior is changed after a flow rate flowing toward the fluid actuator continuously falls below a predetermined value for a predetermined time period and that the fluid pressure control device does not comprise a flow path through which the pressure fluid that has passed through the supply valve is discharged to the exterior. an inlet port connected to the fluid supply source; an outlet port connected to the fluid actuator; a supply valve configured to adjust an area of a flow path connecting the inlet port and the outlet port; and a diaphragm configured to displace a valve element of the supply valve, wherein a pilot chamber is formed on one side of the diaphragm, a feedback chamber communicating with the outlet port is formed on another side of the diaphragm, a pilot pressure supply solenoid valve is disposed in a flow path connecting the inlet port and the pilot chamber, and a pilot pressure discharge solenoid valve is disposed in a flow path through which a pressure fluid in the pilot chamber is discharged to an exterior, and wherein the fluid pressure control device further comprises a control unit configured to control the pilot pressure supply solenoid valve and the pilot pressure discharge solenoid valve, characterized in that the fluid pressure control device is configured to transition from a normal mode, in which a fluid pressure supplied to the fluid actuator is set to an operating pressure, to a standby mode, in which the fluid pressure is set to a standby pressure that is lower than the operating pressure, wherein a transition from the normal mode to the standby mode is performed automatically on the condition that a flow rate flowing toward the fluid actuator continuously falls below a predetermined value for a predetermined time period or the transition is performed manually on the condition that a mode switching signal input from the exterior is changed after a flow rate flowing toward the fluid actuator continuously falls below a predetermined value for a predetermined time period and that the fluid pressure control device does not comprise a flow path through which the pressure fluid that has passed through the supply valve is discharged to the exterior.