PURPOSE: To enable to effect combined control of a plurality of throttle valves and to control only a primary throttle valve, by attaching a hot-starting lever, an auto-cruising lever, a fast-idle lever, a throttle-valve lever, etc. to the primary throttle valve of the throttle valves disposed in a plurality of intak passages.

CONSTITUTION: A primary throttle valve 4 is disposed in a primary intake passage 2 and secondary throttle valves 5 are disposed in respective secondary intake passages 3. A hot-starting lever 11, an auto-cruising lever 12, a throttle- valve lever 13, an interconnecting lever 14, a fast-idle lever 9, etc. are attached to a valve shaft 6 of the primary throttle valve 4. The auto-cruising lever 12 and the throttle-valve lever 13 opens the primary throttle valve 4 by pushing an arm 8 and then opens the secondary throttle valves 5 by pushing the interconnecting lever. On the other hand, in case of opening the primary throttle valve 4 by means of the hot-starting lever 11 and the fast-idle lever 9, the secondary throttle valves 5 are kept closed.