To provide a method of remodeling a toilet from a Japanese style to a Wester style, according to which construction work is relatively easy, and bolts for fixing a Western style toilet bowl can be firmly driven to almost any location.

When an upper portion of a Japanese style toilet bowl 10 is removed, the upper portion of the Japanese toilet bowl 10 is removed down to a predetermined depth from an upper surface of a floor slab 1, and a surface layer 1b on the periphery of the Japanese style toilet bowl 10 is also removed down to the same depth, to thereby form a recess 1c. Then a crack and collapse preventive sheet 20 is bonded to an exposed surface of the Japanese style toilet bowl 10 by an adhesive, and thereafter the interior of the Japanese style toilet bowl 10 is filled with a filler 22. Next a remaining body of the Japanese style toilet bowl 10 and the recess 1c are filled with the self-hardening filler 22. At this time the recess 1c is filled with the filler 22 up to a location that is slightly above a bottom surface thereof, and then a net 23 formed of high-strength fibers is laid on the filler, followed by further feeding the filler 22 onto the net 23, to thereby achieve filling of the recess 1c.