Mass flow controller

Abstract

This invention provides a mass flow controller that can prevent a flow rate change due to a pressure change without sacrificing the speed of response to a change of a flow rate setting value and can be used in a system that can generate a crosstalk. In order to provide the mass flow controller, the mass flow controller has: a control sectionthat calculates an opening control signal to be supplied to a flow rate control valve based on a predetermined calculation formula including at least a flow rate measurement value and a flow rate setting value as parameters and outputs the opening control signal; and a pressure sensor sectionthat measures pressure of a fluid on the upstream side or the downstream side of a flow rate sensor sectionand outputs a pressure detection signal indicating the pressure value. The control sectionuses different calculation formulas for a changing period, which is a predetermined period from a point in time when the flow rate setting value changes by a predetermined amount or more, and a stable period, which is the remaining period, and at least in the stable period, the calculation formula further includes the pressure value as a parameter.