The present invention may relate to an optical sheet unit. According to an embodiment of the present invention, disclosed is an optical sheet unit comprising: a diffusion sheet for diffusing incident light such that the light can be uniformly emitted; a prism sheet unit arranged at the position facing the diffusion sheet to concentrate the light incident from the diffusion sheet; and a bonding layer formed between the prism sheet unit and the diffusion sheet to bond the entire surfaces of the prism sheet unit and the diffusion sheet facing each other.