PURPOSE: To enable suppression of the output from a flowmeter owing to a difference in temp. between air and the wall of a passage by combining the material, shape and size of a support thereby balancing the quantity of the heat transmitted to and from a resistor.

CONSTITUTION: A flowmeter is made into the construction in which a holder 5 is dug in to make a terminal 4 supporting conductively a temp. compensating resistor 2 longer slightly than the terminal 3 of a heating resistor 1. The total of the heat conducted and transmitted by the terminal is made equal on the heating resistor side and the temp. compensating resistor side. The change in the output from the flowmeter owing to the temp. of the wall of the air passage is thus compensated.