Abstract: An electromagnetic flowmeter includes a measuring tube, an electrode, an exciting unit, a signal conversion unit, and a flow rate calculating unit. The signal conversion unit extracts a ?A/?t component irrelevant to a flow velocity of the fluid and a v×B component originating from the flow velocity of the fluid from a resultant electromotive force of an electromotive force ?A/?t, with A, t, v, and B respectively representing a vector potential, a time, a flow velocity, and a magnetic flux density. The flow rate calculating unit extracts a variation component dependent on a parameter from the ?A/?t component, corrects a span which is a coefficient applied to a magnitude V of the flow velocity of the v×B component, and calculates the flow rate of the fluid from the v×B component whose span is corrected.