The invention discloses a scald apparatus using an arc lamp as a light source, which is characterized by comprising a black box with a light emergent hole, wherein, the arc lamp, a convex lens, a concave lens and a light insulation plate are arranged on the light axis passing through the center of the light emergent hole in the black box from far to near; the arc lamp is arranged on the focus of a paraboloidal concave lens; the light emitted by the arc lamp becomes parallel light by the reflecting of the paraboloidal concave lens, enters from one side of the convex lens and converges at the focus F at the other side of the arc lamp; the converged light becomes parallel glowing light spots by the concave lens arranged outside the focus F, and finally passes through an aperture of a light passing axis on the light insulation plate to be projected by the light emergent hole of the black box; the concave lens can be adjusted between the focus F and a point 2F which is two times of the focal length of the convex lens; a photoswitch device for connecting a timer is arranged between the outside of the aperture of the light insulation plate and the light emergent hole of the black box; and the inner side of the aperture of the light insulation plate is provided with a temperature probe for connecting a temperature display.