An exhaust gas cleaning apparatus for an engine has a NOx trapping catalytic converter and a control unit for controlling an intake air throttle valve and a fuel injection timing in accordance with an operating condition of the engine. The device includes a user interface and a system controller. Two positions touched by fingers are detected from detection current to be obtained by the detection electrodes. The first value and the second value each have N bits of precision. In one embodiment, a blower draws air through the DCCC and blows into the heater.