A touch display apparatus including a display unit, a light confinement element, at least one light emitting device, and at least one optical detector is provided. The light confinement element is disposed beside the display unit, and has first and second total internal reflection (TIR) surfaces, and a light incident surface connecting the first and second TIR surfaces. The light emitting device is disposed beside the light incident surface and capable of emitting a light beam which enters the light confinement element through the light incident surface. The first and second TIR surfaces are capable of repeatedly totally reflecting the light beam in the light confinement element, for confining the light beam between the first and second TIR surfaces. When a touch object contacts the first TIR surface, the TIR effect is spoiled, and the touch object reflects a part of the light beam to the optical detector.