EVAPORATED FUEL TREATMENT DEVICE

To provide a technique for accurately diagnosing leakage from a sealing valve when the sealing valve is in a closed state.SOLUTION: When the sealing valve is in a closed state, a control part diagnoses leakage from the sealing valve on the basis of a pressure detected by a first pressure sensor and/or a second pressure sensor at the time a difference between a pressure in a vapor passage on the upstream side further than the sealing valve and a pressure in the vapor passage on the downstream side further than the sealing valve is a first difference, and a pressure detected by the first pressure sensor and/or the second pressure sensor at the time the difference is a second difference different from the first difference.SELECTED DRAWING: Figure 1 【課題】封鎖弁が閉弁状態であるときに、封鎖弁からのリークを精度良く診断することができる技術を提供する。【解決手段】制御部が、封鎖弁が閉弁状態であるときに、前記封鎖弁よりも上流側のベーパ通路内の圧力と前記封鎖弁よりも下流側の前記ベーパ通路内の圧力との差が第１の差であるときの第１圧力センサ及び／又は第２圧力センサの検出圧力と、前記差が前記第１の差と異なる第２の差であるときの前記第１圧力センサ及び／又は前記第２圧力センサの検出圧力とに基づいて、前記封鎖弁からのリークを診断する。【選択図】図１