PURPOSE: To eliminate the generation of a stage difference at a joint part by extending a first and a second roof tile parts from both sides of a ridge line of a corner eaves so as to form a corner roof tile main body, and projecting a piece to be fitted from the lower edge of the end surface of each extension side of the roof tile.

CONSTITUTION: A first roof tile part 1 and a second roof tile part 2 formed into the right-angled triangle are extended from both sides of a ridge line 3 along the eaves line of corner eaves parts C, D so as to form a corner roof tile main body 4. A piece 5 to be fitted is projected from the lower edge of the end surface of each extension side of the first and the second roof tiles 1, 2, and rib parts 6, 7 are provided in each lower surface of the downstream side and the upstream side so as to form a corner roof tile A. The corner roof tile A is roofed in the left corner eaves part C, and thereafter, a lap part of a flat plate roof tile B is fitted on the piece 5 to be fitted of the corner roof tile A, and furthermore, roofed near the right corner eaves part D, cutting the other end of the flat plate roof tile B so as to adjust the execution width. Consequently, since a stage difference is not generated in a joint part of a flat plate roof tile and a corner roof tile, waterproof of the joint part is improved.