PURPOSE: To make a sheet of paper keepable on a conveyor belt with attraction suitable for paper size, by varying the revolution of a fan according to size of the paper being conveyed, while altering the strength of attraction in the fan.

CONSTITUTION: When cassette 30c for B5 size paper is loaded to a paper feeding table 31, a switch 33c is turned on whereby an output "H" is fed to an inverter 46 via a signal line 43 and an output "L" is fed to an AND gate 45 from this inverter 46, while an output from an OR gate 44 to the AND gate 45 is set down to "L" and the AND output "L" is fed to an input terminal 81 of a computer 38 from the AND gate 45. As a result, the output "H" is fed to a driver 37 from an output terminal 83, exciting a solenoid coil 35c of a relay 35 and closing each of make contacts 35A and 35B, and two stator coils 21A and 21B in a fan 21 are energized with continuous rating current in parallel, rotating the fan 21 at a higher speed than in case of B4 size paper, thus the B5 size paper is conveyed as being kept on a conveyor belt.