Provided is a gas flowmeter comprising: a device main body that air-tightly accommodates a fluid to be measured; an inlet part that guides the fluid to be measured into the device main body; an outlet part that discharges the fluid to be measured from the device main body; and a connection part that is connected to the outlet part. The gas flowmeter further comprises: an ultrasonic-type flow rate measuring part that is connected to the connection part and calculates the flow rate of the fluid to be measured that flows internally; and a flow path member that is connected to the connection part and has the same flow path shape as that of the flow rate measuring part. The flow rate measuring part and the flow path member are connected to the connection part in a vertical direction so that a side of an inflow entrance into which the fluid to be measured flows faces downward.
