PROBLEM TO BE SOLVED: To provide a sludge container having an increased effect of cooling solid content in sludge depositing at the bottom thereof and an improved structural soundness.SOLUTION: The sludge container according to the present invention includes: a container body 10 for introducing sludge therein; a receiver 11 in the body 10 for receiving depositing solid content 200, a flow path 12 by which an upper space S1 above the receiver 11 in the body 10 and a lower space S2 below the receiver 11 in the body 10 connect to each other; and a thermal exchanger 13 penetrating the receiver 11 in a vertical direction and opening at lower and upper edges in the lower space S2 and the upper space S1, respectively.