The invention provides an air inlet device comprising an air inlet pipe (9) with an air inlet pipe section (3) which can asway support throttles (7, 24, 37), and the air inlet pipe (9) is divided intoan air pipe (4) and a mixing pipe (5) by separating walls (10, 27, 44) in the downstream of the throttles (7, 24, 37). A fuel nozzle (6) is communicated with the mixing pipe (5). A separating wall inthe upstream of the throttle (37) is formed by a choke cover (39) asway supported in the air inlet pipe (9).