To provide an apparatus for simply and correctly discriminating a material of a photographic film base which discriminates a tetraacetylcellulose (TAC) film.

The apparatus includes: a pair of upper and lower holders 1, 3 openably coupled, and having opposite windows 7, 8; polarization filters 10, 11 provided in the windows 7, 8, and having different polarization directions; a light source unit 19 provided on the back side of the polarization filter 11 in the lower holder 3; and an opening and closing means 27 for attaching or separating both polarization filters 10, 11 by pressures from holding sections 4, 5 in both holders 1, 3.