Film thickness measuring method and device therefor.

摘要

A film thickness measuring method and device therefor which are free from drawbacks caused by errors in a sheet conveying system and an optical system of the device and the like. The optical system is moved over a sheet (3) having a sheet member and a film formed thereon, whose thickness is to be measured, so that the deformation of the conveying system and the optical system is detected in advance. After taking the detection results into account, the thickness measurement is carried out resulting in improving accuracy thereof.