To provide a cement rotary kiln and a repair method capable of preventing a slip and stress of a wear brick and reducing the number of bricks disposed of at the time or repair.

A key brick 14 has a thickness equal to that of the total of the first layer brick 12 and the second layer brick 13, and adheres to a shell 11 so that a relative deviation between the first and the second layer brick and the generation of stress can be prevented. If the residual thickness of the first layer brick 12 is less than an effective residual thickness and the second layer brick 13 is not damaged at the time of repair, the second layer brick is reused and only the first layer brick 12 is repaired. Thus the number of bricks disposed of can be reduced.