Side molded combination type line lights according to the present invention are configured to include: a fixed frame having a basic C-shaped cross sectional structure formed with a closing portion, opposite side walls, and an opening portion, wherein a protruding locking portion for guiding fixation of pieces is formed on each inner side of the opposite side walls, and a side mold coupling end is formed at each of the end portions of the opposite side walls; a diffusion plate coupled with the opening portion of the fixed frame; and a side mold formed in an L-shaped or T-shaped cross section, wherein an engaging portion to be coupled with the side mold coupling end is formed on one of the two types of side molds and coupled with each of the end portions of the opposite side walls of the fixed frame.