PURPOSE: To make judgement regarding the suitability of glass mounting state by fixing a measurement, plate to window glass, and an optical sensor to a body, and measuring and recording the motion amount of the glass at the time of parking and travel for comparison with the predetermined reference data.

CONSTITUTION: A measurement plate 1 is fixed to window glass W mounted on a body B, while a laser sensor 2 is fixed to the body B via a bracket 7 and a stay 8. The sensor 2 causes light to be reflected with the plate 1 for measuring the motion amount of the glass W. An amplifier 3 controls the output of the sensor 2 and a judgement section undertakes the comparative analysis of the motion amount data of the glass W against the predetermined reference data, thereby making judgement about the mounting state of the glass W. Also, a recording section records the motion amount data of the glass W. According to this construction, the motion amount of the glass W can be measured and judged. The mounting state of the glass W can be, therefore, easily inspected, and the results thereof can be fed back to a production line.