To provide an accelerator for a carburator having a simple structure without using linkage which is not drastically increased in size, for interlocking with a throttle valve and operating a piston type accelerator pump.

A cam 33 which is arc-shaped with a throttle valve shaft 8 as the center and having a cam face 33A facing an carburetor main body 1 is provided on the lower surface of a throttle valve lever 10, and the accelerator pump 25 is positioned in parallel with the throttle valve shaft 8 and the upper end of a piston rod 28 is made to contact the cam face 33A. The cam 33 pushes down the piston rod 28 accompanying turning of the throttle valve lever 10 in the throttle valve opening direction, and acceleration fuel of a pump chamber 29 is fed to a suction passage 2.