A semiconductor manufacturing apparatus according to the present invention comprises: a treating unit that treats a substrate to manufacture thereon a semiconductor device; a fluid supplying channel for supplying a fluid required for a treatment of the substrate to the treating unit; a set voltage outputting unit that outputs a set voltage corresponding to a set flow volume of the fluid; a massflow controller disposed on the fluid supplying channel, that controls a flow volume of the fluid based on the set voltage; a first shut-off valve disposed on the fluid supplying channel on an upstream side of the massflow controller; and a second shut-off valve disposed on the fluid supplying channel on a downstream side of the massflow controller. The massflow controller includes: a detecting unit that detects an actual flow volume of the fluid and outputs a corresponding detected voltage; a comparing unit that compares the set voltage with the detected voltage to output an operation signal; and a flow volume adjusting unit that adjusts the flow volume of the fluid based on the operation signal. A storing unit is provided, that stores the detected voltage outputted from the detecting unit of the massflow controller, when the first and the second shut-off valves are closed. A set voltage correcting unit is provided, that corrects the set voltage based on the detected voltage stored in the storing unit, in such a manner that a drift of the detected voltage is compensated when an actual flow volume of the fluid is zero.