Abstract: A control parameter setting device to be incorporated in an image input/processing apparatus which includes a casing having an inside surface having a first color. An elongated channel is formed on the casing to movably receive therein a user-setting member which has a user accessible knob or switch exposed outside the channel to allow a user to move the user-setting member between at least two predetermined positions along the channel, each corresponding to a predetermined set of control parameters of the image input/processing apparatus, and an inside casing extension which is located inside the casing and movable by the user accessible knob. The extension has an inward facing surface having a second color which is significantly contrasty to the first color so that they are optically different remarkably.