To compactly arrange a suction negative pressure sensor for detecting suction negative pressure in a suction passage nearer a downstream side than a throttle valve.

An injector 38 for fuel injection is mounted to a throttle main body 37, and a slide throttle valve type throttle body device 26 is provided with a sliding-type throttle valve 39. The throttle valve 39 is slidably provided to the throttle main body for opening and closing a suction passage 40 formed through the throttle main body 37. A throttle valve chamber 42 that can house the throttle valve 39 formed on the throttle main body to project upward, and a negative pressure passage 47 extending upward from a negative pressure introduction port 50 communicated with the suction passage 40 on a downstream side, and communicated with a negative pressure detection port 55 opened on an upper outside face of the throttle main body is formed on the throttle valve 39. A suction negative pressure sensor 41 connected to the negative pressure detection port is arranged at an upper outside part of the throttle main body 37 nearer the downstream side of the suction passage than the throttle valve chamber 42.