NON-CONTACT TYPE SHAPE MEASURING DEVICE

PURPOSE:To measure a surface shape accurately by detecting distances at two measuring positions apart mutually in an optical axis direction through an optical distance detecting means at respective measuring points, judging whether the measuring points are positioned within a measurable range through the distance detecting means, and computing the shape on proper detected values only. CONSTITUTION:At respective measuring points, the difference of a detected distance at a first measuring position (distance from an optical distance detecting means to a light-irradiated point on an object to be measured) and a detected distance at a second measuring position is computed by a detected value comparing means 44, and a current detected value is judged whether it is proper or not. When the detected value is judged to be proper, the detected value is input to a shape computing means 46. When the detected value is judged to be not proper, a command is sent to a drive control means 42 so as to move the object to be measured in a Z axis direction once again. By the means 46, the surface shape of the object to be measured is computed based on the moved position of the object to be measured determined from the detected results of respective axis scales 24, 26, 28 and the detected value judged to be poper through the means 44, and its result is displayed on a display device 52.