An ink jet printer bed in which a printing object placed on a bed is stably fixed by means of air suction and is printed, is disclosed, which comprises a plurality of upper plates having a plurality of air suction ports on their front surfaces; an intermediate plate which is formed of a guide space of which intermediate portion is open via its upper lower sides, the intermediate plate being assembled to a lower side of the upper plate; a lower plate which is assembled to a lower side of the intermediate portion and is formed of at least one air passage; a connection part which is assembled to each air passage of the lower plate and is connected with a suction pump; and a sensor which detects an air pressure in the interior of the bed and transmits a result of the detection to a controller which controls the operation of the suction pump, so the air pressure of the interior of the bed by the suction pump can be adjusted.