To provide a jet needle holder for a variable venturi type carburetor excellent in durability with a small change of air-fuel ratio even when a running distance of a vehicle is increased.

A guide member 10 is formed in a disk shape, a guide hole 10A is drilled in the center part, and a communication hole is drilled in the sideward of the guide hole 10A. The guide hole 10A has a diameter almost equal to a straight diametric part 9A of a jet needle 9, and the communication hole 10B has an area larger than a maximum annular area formed by the jet needle 9 and a metering hole 8A of a needle jet 8. The guide member 10 is arranged to be fitted in an opening hole 8B provided in the upward of the metering hole 8A of the needle jet 8 further to have a diameter larger than the metering hole 8A, and the jet needle 9 is insertion supported to the guide hole 10A of the guide member 10.