PURPOSE: To obtain the titled apparatus which can inhibit a heat loss and make the entire body of its arrangement small in size, while contriving to simplify a thawing part, by constituting a freezing part with a hollow pipe for freezing forcedly poured sludge into an icicle state, and providing the thawing part for icicle sludge discharged through the outlet of said hollow pipe at a position separated from the thawing part.

CONSTITUTION: When the freezing of sludge forcibly poured from a forcibly pouring part 1 into the hollow pipe 5 of a freezing part 2 is completed, a coolant is withdrawn from a medium chamber 21, and then a heat medium is introduced therein. By said heat medium, the entire surface of the icicle sludge inside the pipe 5 is uniformly thawed to facilitate its sliding motion along its contact surface against the pipe 5. Thereafter, pressure larger than that applied to a pinch valve 14 is applied to unfreezed sludge through the forcibly pouring part 1, to discharge the icicle sludge as such from the pipe 5 through the unfreezed sludge. A crusher 15 for breaking icicle sludge provided at a sludge-discharging part 4 is moved up and down, to rapidly cut the icicle sludge being extruded through the valve 14 into pieces and to drop the cut pieces into a thawing tank 81 provided therebelow. After the discharge of the icicle sludge is completed, the heat medium in the chamber 21 is replaced by the coolant to restart the operation of freezing sludge.