PURPOSE: To prevent such useless operation that an original is printed or a blank printing form is read by mistake from being performed even if the original and the printing form are put into a paper feeding part at a time.

CONSTITUTION: In a printer with a built-in scanner in which a scanner part capable of reading the original and a printing part to print the printing form are incorporated into one device, a discriminating means which consists of a separator 8 installed at a hopper part 7 and a presence of medium detector 9 to detect the presence of the medium on this separator 8 and discriminates between the original and the printing form, and a switching mechanism 12 which switches the feeding path of the medium in accordance with the discriminated result of the discriminating means are provided so that the original and the printing form can be fed from one hopper part 7.