A speed controller comprising: a first flow path and a second flow path configured to allow a first port and a second port each included in a main body portion to be in communication with each other so as to flow pressure fluid, the first flow path including a first check valve permitting only flow from the first port to the second port, the second flow path including a first needle valve for adjusting a flow rate of the flowing pressure fluid, characterized in that: the second flow path is configured to include an opening hole that opens at a center position of the first check valve in a radial direction as a part of the flow path, the first needle valve adjusts the flow rate by allowing a tip portion of a needle shaft to abut on, to be close to, or to proceed into the opening hole so as to change an opening area of the opening hole, the needle shaft being fixed on a piston reciprocately-movably disposed in a cylinder chamber included in the main body portion and also protruding outside the cylinder chamber, the speed controller further comprises a third flow path configured to allow the first port and the cylinder chamber to be in communication with each other so as to flow the pressure fluid, the third flow path including a second check valve permitting only flow from the first port to the cylinder chamber, the speed controller further comprises a fourth flow path configured to allow the cylinder chamber and a discharge opening provided in the main body portion to be in communication with each other to flow the pressure fluid, and the second check valve functions also as an opening and closing valve of the fourth flow path for closing the fourth flow path by movement of a valve element in a direction opening the third flow path and for opening the fourth flow path by movement of the valve element in a direction closing the third flow path. a first flow path and a second flow path configured to allow a first port and a second port each included in a main body portion to be in communication with each other so as to flow pressure fluid, the first flow path including a first check valve permitting only flow from the first port to the second port, the second flow path including a first needle valve for adjusting a flow rate of the flowing pressure fluid, characterized in that: the second flow path is configured to include an opening hole that opens at a center position of the first check valve in a radial direction as a part of the flow path, the first needle valve adjusts the flow rate by allowing a tip portion of a needle shaft to abut on, to be close to, or to proceed into the opening hole so as to change an opening area of the opening hole, the needle shaft being fixed on a piston reciprocately-movably disposed in a cylinder chamber included in the main body portion and also protruding outside the cylinder chamber, the speed controller further comprises a third flow path configured to allow the first port and the cylinder chamber to be in communication with each other so as to flow the pressure fluid, the third flow path including a second check valve permitting only flow from the first port to the cylinder chamber, the speed controller further comprises a fourth flow path configured to allow the cylinder chamber and a discharge opening provided in the main body portion to be in communication with each other to flow the pressure fluid, and the second check valve functions also as an opening and closing valve of the fourth flow path for closing the fourth flow path by movement of a valve element in a direction opening the third flow path and for opening the fourth flow path by movement of the valve element in a direction closing the third flow path. the second flow path is configured to include an opening hole that opens at a center position of the first check valve in a radial direction as a part of the flow path, the first needle valve adjusts the flow rate by allowing a tip portion of a needle shaft to abut on, to be close to, or to proceed into the opening hole so as to change an opening area of the opening hole, the needle shaft being fixed on a piston reciprocately-movably disposed in a cylinder chamber included in the main body portion and also protruding outside the cylinder chamber, the speed controller further comprises a third flow path configured to allow the first port and the cylinder chamber to be in communication with each other so as to flow the pressure fluid, the third flow path including a second check valve permitting only flow from the first port to the cylinder chamber, the speed controller further comprises a fourth flow path configured to allow the cylinder chamber and a discharge opening provided in the main body portion to be in communication with each other to flow the pressure fluid, and the second check valve functions also as an opening and closing valve of the fourth flow path for closing the fourth flow path by movement of a valve element in a direction opening the third flow path and for opening the fourth flow path by movement of the valve element in a direction closing the third flow path.