An inlet 51 is disposed at a position which is on an upper side relative to an axial flow fan 60 and is opposite to a direction of air flow produced by the rotation of the axial flow fan 60, whereas an intercooler 30 is disposed at a position which is on a lower side relative to the axial flow fan 60 and is downstream along the direction of air flow produced by the rotation of the axial flow fan 60, whereby it can be prevented that an air cleaner 50 constitutes a resistance to an air flow to thereby reduce the volume of air which passes through the intercooler 30. Consequently, intake air can be sufficiently cooled to thereby increase the output of an engine 40.