An abnormality sensing device for an evaporation fuel purge system is equipped with a purge passage that connects a canister to an intake passage of an internal combustion engine, a purge pump, a purge control valve, and a valve component that closes and opens the purge passage at a target passage including at least a first purge passage defined between the purge control valve and the intake passage. An abnormality determining portion detects a physical quantity relevant to a pressure change in the target passage in a determination possible state where the purge control valve allows the evaporation fuel to flow through the first purge passage and where the valve component prohibits the evaporation fuel from being supplied to the intake passage.