EVAPORATED FUEL TREATMENT DEVICE

An evaporated fuel treatment device includes a fuel tank that stores fuel for an internal combustion engine, a canister that adsorbs evaporated fuel generated in the fuel tank, a pump that pressurizes and depressurizes a diagnostic target system including the fuel tank, a pressure detection unit that detects pressure in the diagnostic target system, a fuel state detection unit that detects a state of the fuel in the fuel tank, a leakage diagnosis unit that diagnoses leakages of evaporated fuel from the diagnostic target system, the diagnostic target system based on a change in a detection value detected by the pressure detection unit when the pump pressurizes or depressurizes the diagnostic target system, and a diagnosis determination unit that determines whether the leakage diagnosis unit performs the diagnosis based on a change in a state detection value detected by the fuel state detection unit.