Venting valve for colostomy bags, which valve comprise a valve body (1) in which a slide is turn- or push able in order to bring a venting hole (11) in the slide to agreement with an opening (4) in the valve body. The opening (4) in the valve body is extended in the movement direction of the slide and a pin (9) or heel on the face of the slide facing the valve body extends through the opening (4) in the valve body, said pin or heel having a shorter length than the opening in the valve body and a shape corresponding to the shape of the hole in the closed position of the valve body so that this can be moved between an open position and a closed position where the pin or heel is brought in contact with the end surface of the hole. Furthermore the pin or heel is in its free end provided with a laterally protruding collar (10) or extension that on the side of the valve body facing away from the slide is in contact with the valve body and when the valve is closed extend a distance outside the opening (4) in the valve body so that also an area around the air passage is kept free from contaminations.
