To easily find the specific flow factor of a type of gas with high accuracy even if the physical properties of the type of gas are unknown in the case of a pressure-type flow controller.

This pressure-type flow controller calculates an actual flow Qg of an arbitrary fluid according to Qg = Qb×SFF when the arbitrary fluid Gg is assumed to be a flow-controlled fluid (where, Qb is a measured flow of the arbitrary fluid in the flow controller assuming that the flow-controlled fluid is a reference fluid Gb, and SFF is the specific flow factor of the arbitrary fluid Gg relative to the reference fluid Gb). The flow factor SFF is operated according to SFF = Δt(Gb)/Δt(Gg)×T(Gb)/T(Gg), (where, Δt(Gb) is time for which a pressure drop reaches an arbitrary set value under the pressure attenuation characteristic of an orifice with respect to the reference fluid Gb, Δt(Gg) is time for which a pressure drop reaches an arbitrary set value ΔP under the pressure attenuation characteristic of the orifice with respect to the arbitrary fluid Gg, T(Gb) is the temperature of the reference fluid Gb, and T(Gg) is the temperature of the arbitrary fluid Gg).