A drum-shaped grate of an incinerator includes a plurality of cylindrical drums, the grate covering of which is formed of a plurality of suspended middle grate bars which are combined in segments and arrested by fixed grate bars. The adjacent grate bars in the circular direction are suspended on bar carriers and the lateral faces of each two adjacent grate bars are spaced from each other by spacers. The surfaces of the spacers positioned between each two adjacent grate bars and abutting against each other are flat and smooth. Due to a possible relative displacement of the middle grate bars in their longitudinal direction owing to the placing of the spacers between the adjacent bars a clogging of the air slots formed between the grate bars would be prevented.