An evaporative fuel-processing system for an internal combustion engine for use in a vehicle. A passage extends between the fuel tank and the intake passage, for guiding evaporative fuel generated in the fuel tank, for processing, across which a canister is arranged. A first passage and a second passage are connected to the canister. A first valve is arranged across the first passage to allow air to flow into the canister through the first passage and inhibit air containing evaporative fuel from being discharged from the canister through the first passage. A second valve is arranged across the second passage to inhibit air from flowing into the canister through the second passage and allow air containing evaporative fuel to be discharged from the canister through the second passage. A filter is arranged in the first passage.