An EHA system (10) for lifting or lowering a leg of an aircraft includes a hydraulic circuit (101) having a hydraulic actuator (a hydraulic cylinder 2) configured to lift or lower the leg, at least one electric hydraulic pump (3), and a hydraulic path, a pressure sensor (38, 83), a temperature sensor (84), and a control unit (a controller 9) configured to output a control signal for operating the electric hydraulic pump in leg lifting or lowering. The hydraulic circuit includes a pressure increasing element. The control unit performs health monitoring regarding the performance of the electric hydraulic pump based on the pressure of hydraulic fluid, the temperature of hydraulic fluid, and the speed of the electric hydraulic pump during operation of the electric hydraulic pump.