Disclosed is an apparatus for inserting a seal into a slewing bearing including a main body and a pressing unit. The main body is fixed to any one of a first ring and a second ring of the slewing bearing. The pressing unit projects from the main body toward a sealing installation position of the other one of the first ring and the second ring. The pressing unit is installed by pressing a seal supplied from the exterior to the sealing installation position toward the sealing installation position as the first ring and the second ring are relatively rotated. Therefore, the seal is installed at the sealing installation position between the first ring and the second ring of the slewing bearing so that the seal of the slewing bearing can be easily exchanged and an exchange operation time of the seal can be reduced.