PURPOSE: To minimize mis-discrimination as to whether an original is a black and white original or a color original for each user by varying a criterion reference value based on a reference original.

CONSTITUTION: An image pickup means A reads a picture of an object with color separation, an identification means B identifies whether a picture signal inputted from the image pickup means A is a chromatic or achromatic, a discrimination means C discriminates whether a picture of an object is a white and a black picture or a color picture based on the result of identification of the identification means B depending on the discrimination reference. Then a storage means D stores a discrimination reference value, and a discrimination means E decides the discrimination reference value based on a picture signal reading a reference picture by the image pickup means A. The discrimination means E varying the discrimination reference value (threshold level) for white black/color discrimination by using the result of reading the reference original is provided to reduce the mis-discrimination corresponding to the object picture accurately.