The present invention relates to an easily expandable indoors LED lighting device, comprising: a fixing bar which is installed on a ceiling; first and second electrode bars, which are provided on a rear surface of the fixing bar; a socket which is provided at the center of the fixing bar that is provided with the first and second electrode bars; and a bell-shaped reflective portion, which is coupled to the socket, for providing power from the first and second electrode bars to a substrate on the inside of which an LED is mounted. The present invention is lightweight, can be directly installed on the ceiling by coupling, and enables expanded installation of the lighting device that is modularized in accordance with the surface area of the ceiling, thereby providing the advantage of easy installation.