A hydraulic apparatus to be incorporated into a vehicle, comprising: a regulating valve provided in a pipe connected to a wheel cylinder of the vehicle, the regulating valve regulating a pressure of a brake fluid in the pipe; and a control system repeatedly performing an opening and closing operation of the regulating valve based on a target pressure value of the wheel cylinder and a pressure value of the wheel cylinder, wherein the regulating valve is controlled so as to be capable of performing the opening and closing operation repeatedly in an update period of the target pressure value, the update period being preset as a term in which a common target pressure value keeps being used, wherein, when performing a first opening and closing operation of the regulating valve in the update period, the control system determines a holding time of an opening and closing state in the first opening and closing operation of the regulating valve based on the pressure value in the first opening and closing operation of the regulating valve and the target pressure value at a beginning of the update period and, based on the holding time, performs the first opening and closing operation of the regulating valve, wherein, when performing an n-th (n ≥ 2) opening and closing operation of the regulating valve in the update period, the control system determines a holding time of an opening and closing state in the n-th opening and closing operation of the regulating valve based on the pressure value in the n-th opening and closing operation of the regulating valve and the target pressure value at the beginning of the update period and, based on the holding time, performs the n-th opening and closing operation of the regulating valve. a regulating valve provided in a pipe connected to a wheel cylinder of the vehicle, the regulating valve regulating a pressure of a brake fluid in the pipe; and a control system repeatedly performing an opening and closing operation of the regulating valve based on a target pressure value of the wheel cylinder and a pressure value of the wheel cylinder, wherein the regulating valve is controlled so as to be capable of performing the opening and closing operation repeatedly in an update period of the target pressure value, the update period being preset as a term in which a common target pressure value keeps being used, wherein, when performing a first opening and closing operation of the regulating valve in the update period, the control system determines a holding time of an opening and closing state in the first opening and closing operation of the regulating valve based on the pressure value in the first opening and closing operation of the regulating valve and the target pressure value at a beginning of the update period and, based on the holding time, performs the first opening and closing operation of the regulating valve, wherein, when performing an n-th (n ≥ 2) opening and closing operation of the regulating valve in the update period, the control system determines a holding time of an opening and closing state in the n-th opening and closing operation of the regulating valve based on the pressure value in the n-th opening and closing operation of the regulating valve and the target pressure value at the beginning of the update period and, based on the holding time, performs the n-th opening and closing operation of the regulating valve.