An arrangement of a pressure booster for a pressurized fluid, a fluid supply source and a tank, the pressure booster comprising: a pressure boosting unit; and a bypass unit, wherein: the pressure boosting unit includes an input port connected to the fluid supply source and an output port connected to the tank, the pressure boosting unit being configured to boost a pressure of the pressurized fluid supplied to the input port and output the pressure-boosted pressurized fluid from the output port; and the bypass unit includes a bypass flow path having one end connected to the fluid supply source, and another end connected to the output port, and the bypass flow path is provided with a bypass check valve configured to block flow of the pressurized fluid from the output port to the fluid supply source, the input port is connected to the fluid supply source via a main flow path provided in the bypass unit; the bypass flow path is connected to the output port via a merging port provided in the pressure boosting unit; the pressure boosting unit is configured to have a cylinder structure in which drive cylinders (16, 18) are provided on both sides of a pressure boosting cylinder; and the bypass unit is attached to a front face of the pressure boosting cylinder, wherein the input port and the merging port are opened in the front face. the pressure booster comprising: a pressure boosting unit; and a bypass unit, wherein: the pressure boosting unit includes an input port connected to the fluid supply source and an output port connected to the tank, the pressure boosting unit being configured to boost a pressure of the pressurized fluid supplied to the input port and output the pressure-boosted pressurized fluid from the output port; and the bypass unit includes a bypass flow path having one end connected to the fluid supply source, and another end connected to the output port, and the bypass flow path is provided with a bypass check valve configured to block flow of the pressurized fluid from the output port to the fluid supply source, the input port is connected to the fluid supply source via a main flow path provided in the bypass unit; the bypass flow path is connected to the output port via a merging port provided in the pressure boosting unit; the pressure boosting unit is configured to have a cylinder structure in which drive cylinders (16, 18) are provided on both sides of a pressure boosting cylinder; and the bypass unit is attached to a front face of the pressure boosting cylinder, wherein the input port and the merging port are opened in the front face. the pressure boosting unit includes an input port connected to the fluid supply source and an output port connected to the tank, the pressure boosting unit being configured to boost a pressure of the pressurized fluid supplied to the input port and output the pressure-boosted pressurized fluid from the output port; and the bypass unit includes a bypass flow path having one end connected to the fluid supply source, and another end connected to the output port, and the bypass flow path is provided with a bypass check valve configured to block flow of the pressurized fluid from the output port to the fluid supply source, the input port is connected to the fluid supply source via a main flow path provided in the bypass unit; the bypass flow path is connected to the output port via a merging port provided in the pressure boosting unit; the pressure boosting unit is configured to have a cylinder structure in which drive cylinders (16, 18) are provided on both sides of a pressure boosting cylinder; and the bypass unit is attached to a front face of the pressure boosting cylinder, wherein the input port and the merging port are opened in the front face.