To provide a fuel reservoir mechanism of a carburetor improving a shape of a contact part of a fuel control lever and an inflow valve of the carburetor and reducing dispersion of a fuel flow rate.

A fuel control lever 7 is supported free to tilt by a support shaft 8 in a fuel chamber 9 provided on a lower part of a carburetor main body 20 and the fuel control lever 7 is engaged with a lower end part of an inflow valve 5 arranged on a top wall of the fuel chamber 9. A bottom surface 5a making a spherical surface and a small diametrical shaft part 52 projected downward from the bottom surface 5a are provided on a lower end part of the inflow valve 5. An end part 7a of the fuel control lever 7 is made to fork to be engaged with the small diametrical shaft part 52 and is also curved in a circular arc shape to make point-contact with the bottom surface 5a.