In an evaporative fuel processing apparatus, a fuel tank and a canister communicate with each other through a vapor passage, and an intake passage of an internal combustion engine and the canister communicates with each other through a purge passage. The evaporative fuel processing apparatus includes an open/close valve which opens or closes the vapor passage, a switching valve which makes the canister open to the atmosphere or isolates the canister from the atmosphere, a booster pump capable of applying pressure to the canister while the switching valve isolates the canister from the atmosphere, a purge control valve which opens or closes the purge passage, and an ECU which controls the open/close valve, the switching valve, the booster pump and the purge control valve.