An anomaly determination device for an evaporated fuel processing device comprises: an evaporated fuel processing device (60) including a canister (61), a purge passage (62) and a purge valve (66); a first pressure sensor (43) and/or a second pressure sensor (45) for acquiring a purge downstream pressure, a third pressure sensor (53) for acquiring a canister internal pressure, and a PCM (70) that calculates a purge flow rate per unit time based on the purge downstream pressure and an opening degree of the purge valve (66), and calculates an integrated purge flow rate by integrating the purge flow rate, so as to perform an anomaly determination for the evaporated fuel processing device (60) based on the canister internal pressure and the integrated purge flow rate. The PCM (70) uses the canister internal pressure when the integrated purge flow rate becomes a predetermined flow rate or more.