Abstract: An emergency shut-off valve adaptable in a gas supply pipe to shut off the pipe in the time of emergency such as occurrence of an abnormal vibration or gas leak, comprising a hollow body which is open at its top and covered by a cover member, said cover member having secured to its inside central part an iron core around which is wound a coil connected to an external gas leak detector and adapted to magnetize said iron core upon receiving an electric signal from said detector, an actuator provided in said hollow body and having secured to its top face a permanent magnet whereby said actuator is magnetically attached to said iron core, said permanent magnet being arranged such that its upper side has the same polarity as that which appears at the underside of said iron core when it is magnetized so that said actuator will drop because of repulsion therebetween when said iron core is magnetized, said hollow body also having formed in its side wall a gas feed hole and discharge holes, a push-up lever adapted to