The present invention relates to a culture vessel which can be broadly applied to culture, regeneration, manufacture, observation and the like of targets such as cells, organs, and microorganisms. In the culture vessel of the present invention, a first vessel 10 and a second vessel 20 each being a close-bottom, open-top vessel are provided. In the first vessel 10 and the second vessel 20, a sideways-facing opening 12 and a sideways-facing opening 22 are formed. The opening 12 and the opening 22 communicate in a watertight manner when the openings 12, 22 are connected face to face.