Provided is a flowmeter which performs stable large flow volume measurement with improved linearity without increasing sizes of the entire apparatus. The flowmeter is provided with a flow tube (2); a cooling apparatus (3) for partially cooling the flow tube (2); a first temperature detecting section (4) for detecting the temperature of the flow tube (2) cooled by the cooling apparatus (3); a second temperature detecting section (5) for detecting the temperature of the cooling apparatus (3); a third temperature detecting section (6) for detecting the temperature of a non-cooling area (2b) in the upstream of a cooling area (2a) in the flow tube (2); and an information processing section (8), which controls the cooling apparatus (3) to have a difference between the temperature detected by the second temperature detecting section (5) and the temperature detected by the third temperature detecting section (6) to be a prescribed value, and calculates the flow volume of a fluid (F) flowing in the flow tube (2) based on a difference between the temperature detected by the second temperature detecting section (5) and the temperature detected by the first temperature detecting section (4). The second temperature detecting section (5) is arranged in the cooling apparatus (3), in the vicinity of an area where, due to flow of the fluid (F) in the communication pipe, temperature is first affected by the fluid (F).