PURPOSE: To input a mesh original without the generation of moire and decrease in resolving power, by detecting the screen angle of the mesh original previously and varying an aperture angle in conformity with the former angle.

CONSTITUTION: When the mesh original is scanned and inputted, the distance (x) between mesh points A and B on the mesh original is measured previously by using a line sensor 40. Screen pitch (a) is already known, so the screen angle θ is known by finding the distance (x). The angle of an aperture 5 is varied in conformity with the angle θ. Consequently, the picture of the original is obtained as mean density for one mesh point all the time, and variation in density is eliminated to prevent the generation of moire, inputting the original without decreasing the resolving power.