A heat exchange ventilator comprising: an exhaust fan to generate an exhaust air flow flowing from an inside to an outside of a room; a supply fan to generate a supply air flow flowing from the outside to the inside of the room; and a first heat exchanger and a second heat exchanger to carry out heat exchange between the exhaust air flow and the supply air flow, the first heat exchanger and the second heat exchanger each including primary passages through which the exhaust air flow passes and secondary passages through which the supply air flow passes, wherein the first heat exchanger and the second heat exchanger are arranged in a second direction perpendicular to a first direction, the first direction being a direction in which members forming the primary passages and members forming the secondary passages are stacked, the first heat exchanger extends further on a first side in the first direction than the second heat exchanger, the second heat exchanger extends further on a second side in the first direction than the first heat exchanger, the second side being opposite to the first side, a first exhaust air passage (23A, 23C) through which the exhaust air flow flowing out from the primary passages of the second heat exchanger passes, and a first supply air passage (23B, 23D) through which the supply air flow caused to flow into the secondary passages of the second heat exchanger passes are formed on the second side of the first heat exchanger, a second exhaust air passage (24B, 24D) through which the exhaust air flow caused to flow into the primary passages of the first heat exchanger passes, and a second supply air passage (24A, 24C) through which the supply air flow flowing out from the secondary passages of the first heat exchanger passes are formed on the first side of the second heat exchanger, a third supply air passage (26B, 26D) through which the supply air flow caused to flow into the secondary passages of the first heat exchanger passes, and a third exhaust air passage (26A, 26C) through which the exhaust air flow flowing from the first exhaust air passage (23A, 23C) passes are arranged in a third direction perpendicular to the first direction and the second direction, and a fourth exhaust air passage (25B, 25D) through which the exhaust air flow caused to flow into the primary passages of the second heat exchanger passes, and a fourth supply air passage (25A, 25C) through which the supply air flow flowing from the second supply air passage (24A, 24C) passes are arranged in the third direction. an exhaust fan to generate an exhaust air flow flowing from an inside to an outside of a room; a supply fan to generate a supply air flow flowing from the outside to the inside of the room; and a first heat exchanger and a second heat exchanger to carry out heat exchange between the exhaust air flow and the supply air flow, the first heat exchanger and the second heat exchanger each including primary passages through which the exhaust air flow passes and secondary passages through which the supply air flow passes, wherein the first heat exchanger and the second heat exchanger are arranged in a second direction perpendicular to a first direction, the first direction being a direction in which members forming the primary passages and members forming the secondary passages are stacked, the first heat exchanger extends further on a first side in the first direction than the second heat exchanger, the second heat exchanger extends further on a second side in the first direction than the first heat exchanger, the second side being opposite to the first side, a first exhaust air passage (23A, 23C) through which the exhaust air flow flowing out from the primary passages of the second heat exchanger passes, and a first supply air passage (23B, 23D) through which the supply air flow caused to flow into the secondary passages of the second heat exchanger passes are formed on the second side of the first heat exchanger, a second exhaust air passage (24B, 24D) through which the exhaust air flow caused to flow into the primary passages of the first heat exchanger passes, and a second supply air passage (24A, 24C) through which the supply air flow flowing out from the secondary passages of the first heat exchanger passes are formed on the first side of the second heat exchanger, a third supply air passage (26B, 26D) through which the supply air flow caused to flow into the secondary passages of the first heat exchanger passes, and a third exhaust air passage (26A, 26C) through which the exhaust air flow flowing from the first exhaust air passage (23A, 23C) passes are arranged in a third direction perpendicular to the first direction and the second direction, and a fourth exhaust air passage (25B, 25D) through which the exhaust air flow caused to flow into the primary passages of the second heat exchanger passes, and a fourth supply air passage (25A, 25C) through which the supply air flow flowing from the second supply air passage (24A, 24C) passes are arranged in the third direction.