A pinch valve is adapted to hold at least one flexible tube in a tube holding room (7) and comprises a plunger (13) adapted to protrude into the tube holding room and pinch the tube against an opposite side wall (11) thereof. The plunger (13) is controllable to be positioned in at least two different positions, an open position where the tube in the tube holding room (7) is not pinched, and a pinching position where the tube is pinched between the plunger (13) and the opposing wall (11). The pinch valve further comprises a tube retaining means (19) adapted to prevent the tube from escaping from the tube holding room (7), especially when the plunger (13) is in the open position, and which can be pivoted into at least two different positions, a non locking position used during insertion of a tube into the tube holding room (7), and a locking position for retaining a tube inside the tube holding room (7) even when the plunger is in an open position.