An object orientation adjusting device 10 in a roller hearth kiln includes: a first roller group 18 including a plurality of rollers 17 configured to rotate in a direction perpendicular to a conveying direction; a second roller group 20 comprising a plurality of rollers 19 configured to rotate in the direction perpendicular to the conveying direction; a lifting apparatus configured to simultaneously lift the first roller group 18 and the second roller group 20; and first sensors A, A, second sensors B, B, third sensors C, C, fourth sensors D, D configured to detect an orientation of a saggar K on a plane and arranged on both sides of a conveying path in pairs.