PURPOSE: To provide a film type carburetor having a simply constructed cheap means, which corrects air-fuel ratio into proper value according to a change of air density due to a change of temperature.

CONSTITUTION: A thermowax mechanism 16 is installed on the atmosphere side, which is opposite side to a constant fuel chamber 8 by setting a diaphragm 10 between them, and a temperature compensation spring 22, which provides an injection valve opening force for an injection valve opening spring 12 of a fuel valve 7, is inserted between the piston 19 of the thermowax mechanism 16 and the diaphragm 10. The temperature compensation spring 22 reduces a spring load, when temperature increases and air density decreases, so as to suppress opening of the fuel valve 7 to reduce the fuel flow rate, as a result, air-fuel ratio is kept to be a constant value.