A toilet apparatus includes a bowl cleaning unit for mixing a detergent that removes dirt on the inner walls of the bowl with cleaning water which is to be flushed into the bowl. The detergent is stored in a detergent tank which is provided inside a housing forming the outer shell of the toilet apparatus, and is supplied to the water supply channel of the cleaning water from the detergent tank through a detergent supply unit. The detergent tank is accommodated in an internal space of the housing and is concealed inside the housing behind a detachable cover which constitutes a portion of the outer walls of the housing.