A flocculation and sedimentation apparatus has: sedimentation tank that causes flocs in raw water to be sedimented and separated; sludge concentration tank that is surrounded by sedimentation tank and that collects and concentrates the flocs; and raw water supply mechanism having center line that passes through sludge concentration tank, wherein raw water supply mechanism rotates about center line and supplies the raw water to sedimentation tank. Raw water supply mechanism includes: raw water introducing portion that is located on center line and to which the raw water is introduced, raw water supply port that is open at a lower portion of an inner space of sedimentation tank and that supplies the raw water to sedimentation tank, and pipe portion that communicates both with raw water introducing portion and with raw water supply port and that extends above sludge concentration tank in a direction away from center line.