PURPOSE: To provide an air suction/discharge system generating only weak noises for the sucker of a sheet suction/conveyance mechanism.

CONSTITUTION: An air suction/discharge mechanism 5 is constituted of an air cylinder 51, a gear train 52 reciprocating its piston rod 51a, and a drive motor 53 for it. The piston rod 51a is reciprocated by the drive motor 53 at a proper low speed, the air suction/discharge mechanism 5 generates a weak vibration sound, the negative-pressure or positive-pressure air A generated by the air cylinder 51 is fed to a sucker 15 to suck or release a sheet 3 respectively. A room can be kept quiet with no noises when a sheet suction/conveyance mechanism 1 is installed in the room such as an office.