PURPOSE: To correctly adjust fuel injection quantity with the movement of a push rod easily followed to fine change in a direction of lower outside air pressure, by making the shape of an abutting portion with the connecting pin of the push rod be a specific truncated conical shape.

CONSTITUTION: In a high altitude compensator device, an abutting shape between a push rod 43 and a connecting pin 50 has a truncated conical shape, in which a diameter is expanded only in a direction to move the push rod 43 as outside air pressure is reduced from a reference position with the abutting position between the push rod 43 and the connecting pin 50 at the time of low ground travel as a standard. Consequently, force, against the pushing force of the connecting pin 50 of the push rod 43, is not applied when the push rod 43 is moved by a bellows 42 as outside air pressure is lowered. Consequently, the movement of the push rod 43 can be easily followed to fine change in a direction to lower outside air pressure, correctly adjusting the maximum fuel injection quantity.