PURPOSE: To perform a proper starting of carburettor by controlling the opening area of a starter for internal combustion engine in response to the engine temperature and thus supplying starting fuel in accordance with the engine temperature.

CONSTITUTION: A plunger 12 for a starter 11 is disposed in starting fuel conduits 16, 17 which are opened into an intake pipe 14, in such a manner that either one of the conduits 16, 17 may be closed by the plunger 12. The plunger 12 is connected to the primary diaphragm 25 of an actuator 2 in way of a lever and rods 13, 3, 27. In the actuator 2, primary and secondary negative pressure chambers 21, 22 are formed, which are respectively partitioned with the primary and secondary diaphragmes. The primary chamber 21 is communicated to an intake manifold 5 in way of a temperature-responsive opening and shutting valve 41 and a negative pressure delay valve 42, and secondary chamber 22 is also communicated to the same via a temperatre-responsive opening and shutting valve 51 and the negative pressure delay valve 57. Thus the fuel conduit 17 is opened fully at a temperature below a preset lowest temperature level by causing a negative pressure to divided into both chambers 21, 22. On the other hand, at a temprature somewhat higher the preset lowest temperature level, the negative pressure is transmitted only to the primary chamber 21 so as to control the conduit 17 in accordance with the thus-transmitted negative pressure.