A core manufacturing apparatus comprising: a storage unit configured to store core sand; a kneading vessel, which is tubular, configured to be fed with the core sand though a feed port to which the storage unit is coupled; a kneading rod provided inside the kneading vessel so as to extend in a longitudinal direction of the kneading vessel, and configured to knead the core sand by rotating around an axis parallel to the longitudinal direction; and a piston configured to eject the kneaded core sand from one end, in the longitudinal direction, of the kneading vessel, wherein: the kneading vessel is configured to be able to transition between a horizontally lying state and a vertically standing state by turning around a first shaft; the kneading vessel is configured to be fed with the core sand in the horizontally lying state through the feed port that is located on an upper side of the kneading vessel; the piston is configured to eject the core sand downward and pack the core sand into a mold with the kneading vessel in the vertically standing state; the storage unit includes a valve configured to, open and close the feed port with the kneading vessel in the horizontally lying state by turning around a second shaft parallel to the first shaft while remaining in contact with the feed port; a part of the valve has an arc shape and the feed port has a substantially circular shape; and the storage unit is coupled to the kneading vessel so as to be turnable around the second shaft, and is configured to maintain the same posture with the valve in contact with the feed port while the kneading vessel turns. a storage unit configured to store core sand; a kneading vessel, which is tubular, configured to be fed with the core sand though a feed port to which the storage unit is coupled; a kneading rod provided inside the kneading vessel so as to extend in a longitudinal direction of the kneading vessel, and configured to knead the core sand by rotating around an axis parallel to the longitudinal direction; and a piston configured to eject the kneaded core sand from one end, in the longitudinal direction, of the kneading vessel, wherein: the kneading vessel is configured to be able to transition between a horizontally lying state and a vertically standing state by turning around a first shaft; the kneading vessel is configured to be fed with the core sand in the horizontally lying state through the feed port that is located on an upper side of the kneading vessel; the piston is configured to eject the core sand downward and pack the core sand into a mold with the kneading vessel in the vertically standing state; the storage unit includes a valve configured to, open and close the feed port with the kneading vessel in the horizontally lying state by turning around a second shaft parallel to the first shaft while remaining in contact with the feed port; a part of the valve has an arc shape and the feed port has a substantially circular shape; and the storage unit is coupled to the kneading vessel so as to be turnable around the second shaft, and is configured to maintain the same posture with the valve in contact with the feed port while the kneading vessel turns. the kneading vessel is configured to be able to transition between a horizontally lying state and a vertically standing state by turning around a first shaft; the kneading vessel is configured to be fed with the core sand in the horizontally lying state through the feed port that is located on an upper side of the kneading vessel; the piston is configured to eject the core sand downward and pack the core sand into a mold with the kneading vessel in the vertically standing state; the storage unit includes a valve configured to, open and close the feed port with the kneading vessel in the horizontally lying state by turning around a second shaft parallel to the first shaft while remaining in contact with the feed port; a part of the valve has an arc shape and the feed port has a substantially circular shape; and the storage unit is coupled to the kneading vessel so as to be turnable around the second shaft, and is configured to maintain the same posture with the valve in contact with the feed port while the kneading vessel turns.