The sphere-shaped cell aggregate of one embodiment of the present invention includes a core portion including a nerve retina and a covering portion that continuously or intermittently covers at least a part of the surface of the core portion. It is an aggregate. (1) In the neural retina, a neural retinal layer including at least a photoreceptor layer is formed, and the photoreceptor layer is selected from a group consisting of at least photoreceptor cells, photoreceptor precursor cells and retinal precursor cells. The cells contained in the photoreceptor layer are continuously present in the tangential direction of the surface of the core portion, and (2) the covering portions are retinal pigment epithelial cells in contact with each other. (3) The cell aggregate does not contain the crystalline body, vitreous body, cornea and blood vessels, and (4) the retinal pigment epithelial cells do not constitute a continuous epithelial structure with the neuroretinal layer. It is characterized by.本発明の一実施形態のスフェア状細胞凝集体は、神経網膜を含むコア部と、前記コア部の表面の少なくとも一部を連続的に又は断続的に覆う被覆部とを備える、スフェア状細胞凝集体であって、（１）前記神経網膜において、少なくとも視細胞層を含む神経網膜層が形成されており、前記視細胞層は少なくとも視細胞、視細胞前駆細胞及び網膜前駆細胞からなる群から選択される１以上の細胞を含み、前記視細胞層に含まれる細胞が前記コア部の表面の接線方向に連続して存在しており、（２）前記被覆部は、互いに接触する網膜色素上皮細胞を含み、（３）前記細胞凝集体は、水晶体、硝子体、角膜及び血管を含まず、かつ（４）前記網膜色素上皮細胞は、前記神経網膜層とともに連続する上皮構造を構成していないことを特徴とする。
