Abstract: An ozone-processing apparatus for a semiconductor process system includes an airtight process chamber and a lamp chamber, which are partitioned by a window for transmitting ultraviolet rays. A plurality of ultraviolet-ray lamps is arrayed along the window in the lamp chamber. A measurement space is defined between the window and the lamps in the lamp chamber. The lamp chamber is provided with a mount portion to set up a measuring unit therein. The measuring unit includes a sensor to be inserted into the measuring space, for measuring the light quantity of the lamps. The sensor is movable in a direction in which the lamps are arrayed.