The present invention relates to a lamp control device of a construction machine and a lamp control method therefor, wherein the control of a plurality of lamps (for example: a working lamp, a deck lamp, a cabin lamp and a rear lamp) which are provided in a construction machine can be carried out by a first key input means which is a single typical switch button and a second key input means which is provided with a plurality of sub-setting keys such that unnecessary switches are removed from the inside of a cabin, thereby providing a more convenient and simplified equipment operation environment for workers.