An LCD driving inverter to drive a plurality of lamps mounted in an LCD module, includes: a main substrate having an input part connected to an external power source, a conversion circuit converting a direct current provided from the input part into an alternating current, a first transformer connected to the conversion circuit to convert voltage from the conversion circuit and a first output part providing the voltage from the first transformer to at least one of a plurality of lamps; a subsidiary substrate including a second transformer connected to the conversion circuit to convert the voltage from the conversion circuit and a second output part providing the voltage from the second transformer to at least another one of the plurality of lamps; and at least one spacing member disposed between the main substrate and the subsidiary substrate so that the subsidiary substrate is mounted to be spaced from a surface of the main substrate. Thus, the LCD driving inverter and a portable computer including the inverter having a plurality of output parts is minimized in the width dimension.