A gate valve is configured to have a first fluid flow path. In a state where a gate valve pin is at a first pin position, a front end section on an injection hole side of the gate valve pin closes an injection hole. In a state where the gate valve pin is at a second pin position that is more distant from the injection hole than the first pin position, a front end section opens the injection hole to make communication between the first fluid flow path and the injection hole and thereby form a resin supply line. In a state where a sleeve is at a first sleeve position and the gate valve pin is at the first pin position, a second fluid flow path is formed in the gate valve to connect an injection hole-side end of the first fluid flow path to outside of the gate valve and is made to communicate with the first fluid flow path and thereby form a cleaning line.