In this throttle control device, the device body secured to a steering wheel is provided with a throttle lever for pulling a control cable and the cover is attached to the upper part of the device body. The throttle control device includes a protruded rim that is formed on one of the outer surfaces of the upper both side walls of the device body and the inner surfaces of both side parts of the cover, a recessed groove capable of slidably engaging with the rim is slantingly formed in the other, the protruded rim is engaged with the recessed groove and slid, and the cover is locked to the device body at its slid end whereby the cover is fixed onto the device body.