An object of this invention is to provide a superior mass flow meter or the like that can flexibly cope with a change of a sample fluid such as a gas kind without requiring a special troublesome labor and that can measure a flow rate with high accuracy. The mass flow meter comprises a sensor section that detects a flow rate of a sample fluid flowing in a flow channel, a setting section that sets a flow rate characteristic function that is intrinsic to each fluid to determine a flow rate based on a flow rate detected value output by the sensor section and an instrumental error correction parameter that is independent from the flow rate characteristic function and common to multiple sample fluids to correct an instrumental error of each mass flow meter, and a flow rate calculating section that calculates a flow rate measurement value of the sample fluid by applying the flow rate characteristic function and the instrumental error correction parameter to the flow rate detected value.