To be able to reliably prevent wash water from flowing from a sanitary washing toilet seat to a toilet bowl body, and then overflowing from a toilet bowl by devising the storage method of the wash water.

A toilet apparatus includes: a sanitary washing toilet seat 30, attached to a toilet bowl body 1, for washing private parts of a human body; a water supply tank 4 for supplying wash water to the interior of the sanitary washing toilet seat 30 to wash the private parts of the human body; a flow sensor (small) 14 for detecting the supply amount or time of the wash water for washing the private parts of the human body supplied to the interior of the sanitary washing toilet seat 30 from the water supply tank 4; and a control unit 8 for receiving a shower water quantity signal from the flow sensor (small) 14 and controlling the water supply tank 4 so as to supply a predetermined quantity of the wash water for washing the private parts of the human body to the interior of the sanitary washing toilet seat 30 based on the shower water quantity signal.