To perform communication or non-communication between arbitrary output and input ports.

This diaphragm valve 1 includes: a valve body 2 having three or more outlet/inlet ports 11, 12, 13; diaphragms 25, 26, 27 opened and closed to valve seats 20, 21, 22 formed on the valve body; and opening and closing mechanisms 30, 31, 32 opening and closing the diaphragms. The outlet/inlet ports are communicated with each other by passages 15, 16, 17 connected thereto through a branch part 14 in the interior of the valve body, and each passage has a valve seat between the outlet/inlet port and the branch part. In the diaphragm valve including the valve body having three or more outlet/inlet ports, the diaphragm opened and closed to the valve seat formed on the valve body, and the opening and closing mechanism opening and closing the diaphragm, the outlet/inlet ports have passages individually connected to another outlet/inlet port in the interior of the valve body, and each passage has a valve seat between two output/inlet ports.