To provide an installation structure of a toilet bowl, which can correct the inclination of a tank as in the case of a conventional one, without providing a base of the bowl with a margin for contact with the tank.

In this toilet bowl, the tank for supplying flushing water to the bowl is fixed to the bowl via a protrusive contact part which is coupled to the tank. Additionally, the tank made of a resin and having the protrusive contact parts has a reinforcing part which is not in contact with the bowl in a no-load state, and which is in contact with the bowl when a load acts on the tank.