PURPOSE: To make valve/flange pipe connection simply and smoothly when a flange type valve is to be connected with the flange of a flange pipe through a ring joint, by preventing slipping-off of the ring joint, and to prevent influx of impurities into the pipeline.

CONSTITUTION: A flange 3 provided with a ring joint seat 3a having a ring- shaped groove 3c, in which a ring joint 1 is fitted, is furnished in the neighborhood of inlet/outlet 6, 7 of the body 2 consisting of fluid inlet/outlet 6, 7, fluid passage 5, valve chest 8 and valve seat 9 and is connected with the flange of a flange pipe through the ring joint 1, and thus a flange type valve is achieved. A support, 4 to support the ring joint 1 in the condition, that it is fitted in the groove 3c, is interposed between the ring joint 1 and the flange 3 of the body 2.