EVAPORATED FUEL TREATMENT APPARATUS

An evaporated fuel treatment apparatus includes a canister, a purge passage, a purge pump, a purge valve, and a controller for executing purge control. The controller is configured to switch the purge valve to a closed state or an open state once, subsequently set a concentration sensing flag to ON, and then detect a purge concentration based on a pump downstream pressure or a pump differential pressure at a predetermined timing elapsed by a predetermined time from setting of the concentration sensing flag to ON.