A lighting device comprising: a light source module comprising at least one light source disposed on a printed circuit board, and a resin layer disposed on the printed circuit board so that the light source is embedded; a light reflection member comprising a first part and a second part, the first part disposed on a side surface of the resin layer and the second part disposed on another side surface of the resin layer, and the first part disposed on a side surface of the printed circuit board and the second part disposed on another side surface of the printed circuit board; and a diffusion plate having an upper surface disposed on the light source module and a side wall which is integrally formed with the upper surface and formed to extend in a lower side direction, and which is adhered onto the light reflection member, wherein a first separated space is disposed between the light source module and the upper surface of the diffusion plate, and the first part of the light reflection member is disposed on a side surface of the first separated space, and the second part of the light reflection member is disposed on another side surface of the first separated space, and characterized in that the light source module further comprises an optical pattern layer disposed on the resin layer, wherein the optical pattern layer comprises: a first optical sheet disposed on an upper surface of the resin layer; a second optical sheet disposed on the first optical sheet; an optical pattern and an adhesive layer disposed between the first optical sheet and the second optical sheet; and a second separated space formed in the adhesive layer disposed around the optical pattern for separating the adhesive layer from the optical pattern. a light source module comprising at least one light source disposed on a printed circuit board, and a resin layer disposed on the printed circuit board so that the light source is embedded; a light reflection member comprising a first part and a second part, the first part disposed on a side surface of the resin layer and the second part disposed on another side surface of the resin layer, and the first part disposed on a side surface of the printed circuit board and the second part disposed on another side surface of the printed circuit board; and a diffusion plate having an upper surface disposed on the light source module and a side wall which is integrally formed with the upper surface and formed to extend in a lower side direction, and which is adhered onto the light reflection member, wherein a first separated space is disposed between the light source module and the upper surface of the diffusion plate, and the first part of the light reflection member is disposed on a side surface of the first separated space, and the second part of the light reflection member is disposed on another side surface of the first separated space, and characterized in that the light source module further comprises an optical pattern layer disposed on the resin layer, wherein the optical pattern layer comprises: a first optical sheet disposed on an upper surface of the resin layer; a second optical sheet disposed on the first optical sheet; an optical pattern and an adhesive layer disposed between the first optical sheet and the second optical sheet; and a second separated space formed in the adhesive layer disposed around the optical pattern for separating the adhesive layer from the optical pattern. a first optical sheet disposed on an upper surface of the resin layer; a second optical sheet disposed on the first optical sheet; an optical pattern and an adhesive layer disposed between the first optical sheet and the second optical sheet; and a second separated space formed in the adhesive layer disposed around the optical pattern for separating the adhesive layer from the optical pattern.