A toilet apparatus according to an embodiment includes a toilet seat, a main part, a toilet, a tank, and a radio wave sensor. The toilet seat is pivotally supported by the main part to be openable and closable. The toilet is provided under the main part. The main part is placed on the toilet. The tank is provided inside the toilet. Water for washing the toilet is stored in the tank. The radio wave sensor is disposed higher than the tank. The radio wave sensor detects a human body by radiating a radio wave frontward of the main part.