An ink jet recording apparatus, comprising: a recording medium supplier, an image recorder, a fixing unit; and a recording medium ejector; the image recorder is configured to discharge ink onto a sheet member passed from the recording medium supplier to form an image; the fixing unit is provided downstream from the image recorder in the conveyance direction of a recording medium, and is configured to fix ink on the recording medium passed from the image recorder; and a sheet member conveyance apparatus that is configured to convey a sheet member on which ink discharged from image recorder has landed, wherein the sheet member conveyance apparatus comprises: a conveyer (21,31) which is configured to move a conveyance member (211, 311, 711) in a conveyance direction to convey a sheet member placed on a mounting surface of the conveyance member (211, 311, 711); a ventilation member (223, 323) which is provided on a side opposite to the mounting surface of the conveyance member (211, 311, 711) along a movement path in the conveyance direction of the conveyance member (211, 311, 711), and which is configured to ventilate in a direction perpendicular to the mounting surface; wherein the fixing unit comprises an air chamber which is provided on the side opposite to the mounting surface of the conveyance member along the movement path in a range including a region overlapping with the ventilation member as seen in the direction perpendicular to the mounting surface, so that ventilation between the air chamber and a mounting surface side of the conveyance member is maintained through vents provided in the conveyance member; and a suction unit which is configured to suck air from the side opposite to the mounting surface of the conveyance member through the air chamber to adsorb the sheet member on the mounting surface of the conveyance member, wherein the air chamber comprises: a first section within a predetermined range in the conveyance direction; and a second section which is provided downstream from the first section in the conveyance direction, and which is ventilated along a ventilation path through the vents and the ventilation member, and the ventilation member is provided such that, when the suction unit sucks air from the air chamber, pressure loss in a ventilation path from the mounting surface side of the conveyance member to the first section is smaller than pressure loss in a ventilation path from the mounting surface side of the conveyance member to the second section. a recording medium supplier, an image recorder, a fixing unit; and a recording medium ejector; the image recorder is configured to discharge ink onto a sheet member passed from the recording medium supplier to form an image; the fixing unit is provided downstream from the image recorder in the conveyance direction of a recording medium, and is configured to fix ink on the recording medium passed from the image recorder; and a sheet member conveyance apparatus that is configured to convey a sheet member on which ink discharged from image recorder has landed, a conveyer (21,31) which is configured to move a conveyance member (211, 311, 711) in a conveyance direction to convey a sheet member placed on a mounting surface of the conveyance member (211, 311, 711); a ventilation member (223, 323) which is provided on a side opposite to the mounting surface of the conveyance member (211, 311, 711) along a movement path in the conveyance direction of the conveyance member (211, 311, 711), and which is configured to ventilate in a direction perpendicular to the mounting surface; wherein the fixing unit comprises an air chamber which is provided on the side opposite to the mounting surface of the conveyance member along the movement path in a range including a region overlapping with the ventilation member as seen in the direction perpendicular to the mounting surface, so that ventilation between the air chamber and a mounting surface side of the conveyance member is maintained through vents provided in the conveyance member; and a suction unit which is configured to suck air from the side opposite to the mounting surface of the conveyance member through the air chamber to adsorb the sheet member on the mounting surface of the conveyance member, wherein the air chamber comprises: a first section within a predetermined range in the conveyance direction; and a second section which is provided downstream from the first section in the conveyance direction, and which is ventilated along a ventilation path through the vents and the ventilation member, and a first section within a predetermined range in the conveyance direction; and a second section which is provided downstream from the first section in the conveyance direction, and which is ventilated along a ventilation path through the vents and the ventilation member, and the ventilation member is provided such that, when the suction unit sucks air from the air chamber, pressure loss in a ventilation path from the mounting surface side of the conveyance member to the first section is smaller than pressure loss in a ventilation path from the mounting surface side of the conveyance member to the second section.