To measure a long-sized sample having an arbitrary size efficiently as well as highly accurately by providing a sample stage movable beyond the travel range of a stage movable along a cross direction.

A long-sized sample 36 is moved on a cross-moving stage 2 formed to allow the read of displacement, and detected via an optical microscope, thereby measuring the length or the shape of each lead frame of the long-sized sample 36. A sample stage 42 is movable beyond the travel range of the cross-moving stage 2, and fitted with a photo detector 44 for detecting transmitted light through the sprocket holes of' the long-sized sample 36. In other words, when the long-sized sample 36 is set on the sample stage 42 and a motor 66 is rotated, the torque of the motor 66 is converted into a linear motion via a pinion 64 and a rack 62. As a result, a moving body 48 travels and the long-sized sample 36 fixed to a sample seat 50 travels in an X-direction along a base 46.