When fuel tank internal pressure is at a first predetermined pressure P1 or above over a first predetermined time length t1, a fuel tank shutoff valve is opened and a vapor solenoid valve is closed to make piping internal pressure equal to the fuel tank internal pressure. Then, a purge control valve is opened to emit fuel evaporative gas from the fuel tank into an intake passage. When the fuel tank internal pressure is continuously at a second predetermined pressure P2 or below over the first predetermined time length t1, the fuel tank shutoff valve is closed, and when accumulated volume in high-pressure purge finishing phase reaches a second predetermined volume iv2 or above, the vapor solenoid valve is opened. When the accumulated volume in high-pressure purge finishing phase reaches a first predetermined volume iv1 or above, the purge control valve is opened and the engine is stopped.