To suppress wear of a lateral guide member for a movable grate parts, and hence eliminate the need of complicated exchange of the lateral guide member.

There is provided a thrust grate including stationary grate parts and longitudinally movable grate parts, and the thrust grate is connected with a member for laterally guiding the thrust grate. The aforementioned member is formed with a tensile member 3 which is arranged oppositely, and which is pulled perpendicularly to a movement direction of the grate and substantially horizontally between the movable grate parts 2 and the stationary structure part 1.