THICKNESS MEASURING DEVICE OF COLORED FILM AND THICKNESS MEASURING METHOD OF COLORED FILM

PROBLEM TO BE SOLVED: To provide a thickness measuring device of a colored film and a thickness measuring method capable of measuring the film thickness precisely without being influenced by absorption of a pigment included in the colored film and by high order light, and measuring the film thickness of a photoresist before pattern exposure, when measuring the colored film of a color filter for a liquid crystal display device by a spectral interference method. SOLUTION: Maximal and minimal wavelengths generated by interference are wholly acquired from a spectral reflectance by using wavelengths over 800 nm, and the film thicknesses in temporary interference orders corresponding to the wavelengths for giving the maximal and minimal values are calculated on plurals in all the pertinent orders, and the mean value of the thickness values is used as the thickness of the colored film by adopting the interference order having the least dispersion of the thickness values as the true interference order.