To achieve a flowmeter capable of outputting an alarm when the number of pulses to be output is inconsistent with the number of actually output pulses, by installing a pulse diagnostic section which diagnoses the number of pulses to be output by a pulse output section and the number of actually output pulses.

The flowmeter provided with a flow rate sensor detecting a flow rate of a fluid flowing through piping, the pulse output section generating a pulse signal having the number of pulses appropriate to this flow rate, and a pulse output end outputting the pulse signal; compares the number of pulses to be output by the pulse output section and the number of pulses output to a route from the pulse output section to the pulse output end, and outputs an alarm signal based on a comparison result.