We have developed a new optical sensor that measures the width and the surface profile of a steel plate or strip. The key feature of the new multifunction sensor is that it can measure the width and the height of the object at the same time. To achieve this, we applied laser scanning and a custom-made photo diode (PD) module which consists of dual line PD array with a layout in which 1 array is shifted by half an element pitch. We have constructed test equipment to verify the principle of the new multifunction sensor. It consists of a laser scanning unit and a laser detection unit. The scanning unit has a polygon mirror which scans a collimated laser beam and irradiates it onto the steel plate. A laser detection unit receives the laser beam which is reflected from the surface of the steel plate and images it to the PD module, while the beam spot scans on the plate. In this paper, we show the principles of the new method of sensing width and height, and afterwards we describe the evaluation results of the new multifunction sensor by using the test equipment.