An object of the present invention is to provide a cell culture vessel which is simple in structure and easy to handle, and is capable of preventing damage to the cells when separated, promoting transport of nutrients and excretion of effete matter, and elevating the culturing efficiency improving effect by the structural features. In order to attain the above object, there is provided a cell culture vessel including a culture section provided with a plurality of projections having an equivalent diameter smaller than the cells to be cultured and the culture section side walls enclosing the culture section, wherein the distance between an arbitrary position on the culture section/side wall boundary line and the nearest projection is smaller than the diameter of the cells to be cultured. The effect of the projections in the vessel given to the cultured cells is enhanced.