Abstract: An apparatus for preventing the discharge of evaporated fuel gas including a charcoal canister for absorbing and temporarily storing fuel gas, a purge port placed in the intake passage of the carburetor of the engine, a passage for evaporated fuel connecting the purge port with the charcoal canister so that the evaporated fuel that has become stored in the charcoal canister is supplied to the engine during operation of the engine by means of the negative pressure in the air passage, a second purge port which opens to a venturi section of the carburetor, a second passage for evaporated fuel which connects the second purge port with the charcoal canister and a check valve which is placed in the second passage which allows a flow only in the direction of the venturi section.