PURPOSE: To concurrently open or close the other valve interlocked with one valve by transmitting the opening/closing force to the other valve provided with a torque adjusting mechanism via a transmission mechanism containing a belt and the like with the handle action of one valve.

CONSTITUTION: A serial multiple-valve device for controlling the flow of the flammable gas used in the semiconductor process is provided with an A-axis valve main body A reciprocating a control valve 4 screwed to a valve screw section 5 through the rotating action of a rotating handle 8 via a valve rod 3 to open or close a valve seat section 10 and a B-axis valve auxiliary body B reciprocating a control valve 15 screwed to a valve screw section 16 through the rotation of a valve rod 14 to open or close a valve seat section 21. The valve opening/closing force of the A-axis valve main body A is transmitted to the B-axis valve auxiliary body B via a transmission mechanism section C wound with a chain 7 across rotary gears 6, 17. The driving torque of the B-axis valve auxiliary body B can be freely adjusted by a torque adjusting mechanism section 19 including a friction plate 18.