PURPOSE: To prevent generation of interference fringes, by providing a pressing means, which can adhere closely to the film picture face, in the device fixed part where the slide film is mounted and by sucking air between the pressing means and the film face to cause them to adhere to each other.

CONSTITUTION: Window 51 of film holder 50 has window frame 52, and the size of window 52 is caused to coincide with the size of film face (b) of slide film B. Air between film face (b) and mat surface 55a is sucked by the suction pump to cause them to adhere closely to optical glass 55, and therefore, interference fringes are not generated. Holder 50 has flat spring 55 fixed to side faces of grooves 50a and 50b for the purpose of facilitating fitting and removal operations of slide film B, and therefore, slide film B can be prevented from being caught in window frame 52 when it is mounted.