The Travelling Beam Device is used for detecting surface irregularities in both concrete and asphalt pavements. The apparatus consists essentially of a 3 meter length beam with rigid wheels at the extremities and a wheel at the middle, which can detect any vertical deviation of the surface from a straight-line between the two wheels at the ends of the machine. Measuring capacity of the device is ±25 mm with 5mm increments. It comprises manual dye marker which can mark irregular surfaces of the road.