To provide an engine throttle device detecting the opening degree of a throttle valve with high accuracy.

The engine throttle device 28 includes in a throttle body 21: a throttle opening degree sensor 46 connected to a throttle shaft 23 for detecting the opening degree of the throttle valve 22; an electric motor 41 rotating the throttle shaft 23 by a command from a control device to open and close the throttle valve 22; a return spring 44 biasing the throttle valve 22 in the closing direction; and an adjust screw 55 regulating the close position of the throttle valve 22. The control device performs control for once opening the throttle valve 22 in a closed state to a target opening degree θ1 and closing the throttle valve on a fixed condition by the electric motor 41, prior to engine starting, when an engine is operated to start by ignition operation or the like.