1. A measuring apparatus for measuring data on a shape of a substrate surface, the apparatus comprising: an irradiating unit that irradiates the substrate with light; a detecting unit that detects the light scattered from the substrate; a sampling unit that samples detection results of the detecting unit at a specific frequency; and a processing unit, adapted to: convert sampling results of the sampling unit into three-dimensional data based upon signal intensity, detection intervals, and a frequency of detection that correspond to the detection results; and obtain the shape of the substrate by use of results of the three-dimensional data conversion.