An apparatus for treatment of an organic waste comprising: a first sealed vessel having a first closed space for receiving the organic waste thereto; steam jet means for blowing off a steam into the first sealed vessel at a temperature and a pressure for carbonizing the waste; a discharge port provided on a bottom side of the first sealed vessel, and having a first opening/closing mechanism; and separating and recovering means for separating and recovering a treated waste and aliquid respectively from a mixture of the treated waste and liquid only by a direct discharge operation from the discharge port, the separating and recovering means comprising: a recovery unit for the liquid including a second closed space different from the first closed space of the first sealed vessel, and communicating with the inside of the first sealed vessel via the discharge port, wherein the separating and recovering means comprise a gravity flow recovery mechanism for recovering the liquid by causing the liquid in the sealed vessel to flow by gravity via the discharge port from the inside of the sealed vessel down to the recovery unit, wherein said gravity flow recovery mechanism comprises a liquid recovery flow passage for communicating and connecting the discharge port of the first sealed vessel and the recovery unit, wherein said liquid recovery flow passage is arranged so as to be horizontal or inclined downward from the side communicating with the discharge port to the side of the recovery unit, and is provided with a second opening/closing mechanism for selectively switching the communication state so as to close the liquid recovery flow passage during the treatment of the waste in the first sealed vessel, and so as to open the second opening/closing mechanism for recovering the liquid via the liquid recovery flow passage after the treatment, characterized by agitating means for agitating the waste in the first sealed vessel; and in that the gravity flow recovery mechanism comprises equal pressure forming means for causing the first closed space of the first sealed vessel and the second closed space of the recovery unit to have an equal pressure before a recovery operation of the liquid, and in that the first sealed vessel is formed into a horizontal barrel shape provided with the discharge port on the bottom side at a center portion in the left and right direction, and the diameter gradually decreases from the center portion in the left and right direction toward both left and right ends, the agitating means comprises a rotation shaft provided in the widthwise direction in the sealed vessel, and is supported axially and rotatably, and an agitating blade attached to the rotation shaft, and comprises a portion widening in the circumferential direction of the rotation shaft, and the length of the agitating blade from the rotation shaft to a blade tip is configured so as to be long at a center position in the lengthwise direction of the rotation shaft, and gradually decreases toward the both ends corresponding to the horizontal barrel shape of the sealed vessel. a first sealed vessel having a first closed space for receiving the organic waste thereto; steam jet means for blowing off a steam into the first sealed vessel at a temperature and a pressure for carbonizing the waste; a discharge port provided on a bottom side of the first sealed vessel, and having a first opening/closing mechanism; and separating and recovering means for separating and recovering a treated waste and aliquid respectively from a mixture of the treated waste and liquid only by a direct discharge operation from the discharge port, a recovery unit for the liquid including a second closed space different from the first closed space of the first sealed vessel, and communicating with the inside of the first sealed vessel via the discharge port, wherein the separating and recovering means comprise a gravity flow recovery mechanism for recovering the liquid by causing the liquid in the sealed vessel to flow by gravity via the discharge port from the inside of the sealed vessel down to the recovery unit, wherein said gravity flow recovery mechanism comprises a liquid recovery flow passage for communicating and connecting the discharge port of the first sealed vessel and the recovery unit,