To prevent freezing in the inner wall of a resin made throttle body and a throttle valve at a low-temperature time.

Since an EGR passage is formed in a joined surface between the first body 10 of an air inlet side and the second body 20 of an air outlet side so as to surround the full periphery of a throttle valve 31, water contained in flowing-in air from the internal space 19 of an outer pipe 11 is prevented from freezing on the inner walls of inner pipes 12 and 22 and the surface of the throttle valve 31 and, for example, stuck ice blocks are not melted. Accordingly, the throttle valve 31 adjusts the air flow rate of the internal space 14 of the inner pipe 12 well without its turn being disturbed at a low-temperature time. Also, since an air inlet side space 13 is opened in the air inlet side and closed in the joined surface between the first and second bodies 10 and 20, water or soils flowing in through the inner wall of the outer pipe 11 are stayed and the operation failure of the throttle valve 31 is prevented.