A hydraulic unit (1,101) comprising: a hydraulic circuit fluidly connectable to a hydraulic actuator; and a control device configured to control the hydraulic circuit, the hydraulic circuit including: a hydraulic oil tank configured to store hydraulic oil; a hydraulic pump (12,112) configured to supply the hydraulic oil to the hydraulic actuator from the hydraulic oil tank; a discharge flow path fluidly connected to a discharge side of the hydraulic pump (12,112) and connectable to the hydraulic actuator; a valve configured to block a flow of the hydraulic oil in the discharge flow path; a pressure sensor configured to detect a pressure of the hydraulic oil in a flow path portion, between the valve and the hydraulic pump (12,112), of the discharge flow path, wherein when a rotational frequency of the hydraulic pump (12,112) exceeds a predetermined first determination rotational frequency or when a discharge flow rate of the hydraulic pump (12,112) exceeds a predetermined first determination discharge flow rate (Ql), in a pressure holding state in which the hydraulic pump (12,112) is controlled such that the pressure detected by the pressure sensor is held at a predetermined pressure while the valve is blocking the flow of the hydraulic oil, the control device determines that the hydraulic circuit is abnormal. a hydraulic circuit fluidly connectable to a hydraulic actuator; and a control device configured to control the hydraulic circuit, the hydraulic circuit including: a hydraulic oil tank configured to store hydraulic oil; a hydraulic pump (12,112) configured to supply the hydraulic oil to the hydraulic actuator from the hydraulic oil tank; a discharge flow path fluidly connected to a discharge side of the hydraulic pump (12,112) and connectable to the hydraulic actuator; a valve configured to block a flow of the hydraulic oil in the discharge flow path; a pressure sensor configured to detect a pressure of the hydraulic oil in a flow path portion, between the valve and the hydraulic pump (12,112), of the discharge flow path, wherein when a rotational frequency of the hydraulic pump (12,112) exceeds a predetermined first determination rotational frequency or when a discharge flow rate of the hydraulic pump (12,112) exceeds a predetermined first determination discharge flow rate (Ql), in a pressure holding state in which the hydraulic pump (12,112) is controlled such that the pressure detected by the pressure sensor is held at a predetermined pressure while the valve is blocking the flow of the hydraulic oil, the control device determines that the hydraulic circuit is abnormal. a hydraulic oil tank configured to store hydraulic oil; a hydraulic pump (12,112) configured to supply the hydraulic oil to the hydraulic actuator from the hydraulic oil tank; a discharge flow path fluidly connected to a discharge side of the hydraulic pump (12,112) and connectable to the hydraulic actuator; a valve configured to block a flow of the hydraulic oil in the discharge flow path; a pressure sensor configured to detect a pressure of the hydraulic oil in a flow path portion, between the valve and the hydraulic pump (12,112), of the discharge flow path, wherein when a rotational frequency of the hydraulic pump (12,112) exceeds a predetermined first determination rotational frequency or when a discharge flow rate of the hydraulic pump (12,112) exceeds a predetermined first determination discharge flow rate (Ql), in a pressure holding state in which the hydraulic pump (12,112) is controlled such that the pressure detected by the pressure sensor is held at a predetermined pressure while the valve is blocking the flow of the hydraulic oil, the control device determines that the hydraulic circuit is abnormal.