A gripper device comprising: a carrier device movably provided; a plurality of gripper pairs attached to the carrier device through supports; and a distance adjustment mechanism that adjusts a distance between one gripper (31, 33) and another gripper (32, 34) included in each of the plurality of gripper pairs, each of the plurality of gripper pairs for holding one bag, wherein one side edge of the bag being held by the one gripper (31, 33), another side edge of the bag being held by the another gripper (32, 34), characterized in that the one gripper (31, 33) and the another gripper (32, 34) included in each of the plurality of gripper pairs are attached to the carrier device through a same support, the distance adjustment mechanism swings at least one of the one gripper (31, 33) and the another gripper (32, 34) included in each of the plurality of gripper pairs around the same support in such a manner that a distance between the one gripper (31, 33) and the another gripper (32, 34) is adjusted, the plurality of gripper pairs includes a first gripper pair having first and second grippers (31, 32), and a second gripper pair having third and fourth grippers (33, 34), the distance adjustment mechanism includes a force applying mechanism capable of applying force to the first gripper, and a force transmitting mechanism that transmits force between the first gripper pair and the second gripper pair, the force applying mechanism swings the first gripper to adjust a distance between the first gripper and the second gripper, and the force transmitting mechanism transmits the force applied to the first gripper from the force applying mechanism, to the fourth gripper to swing the fourth gripper in such a manner that a distance between the third and fourth grippers (33, 34) is adjusted. a carrier device movably provided; a plurality of gripper pairs attached to the carrier device through supports; and a distance adjustment mechanism that adjusts a distance between one gripper (31, 33) and another gripper (32, 34) included in each of the plurality of gripper pairs, each of the plurality of gripper pairs for holding one bag, wherein one side edge of the bag being held by the one gripper (31, 33), another side edge of the bag being held by the another gripper (32, 34), characterized in that the one gripper (31, 33) and the another gripper (32, 34) included in each of the plurality of gripper pairs are attached to the carrier device through a same support, the distance adjustment mechanism swings at least one of the one gripper (31, 33) and the another gripper (32, 34) included in each of the plurality of gripper pairs around the same support in such a manner that a distance between the one gripper (31, 33) and the another gripper (32, 34) is adjusted, the plurality of gripper pairs includes a first gripper pair having first and second grippers (31, 32), and a second gripper pair having third and fourth grippers (33, 34), the distance adjustment mechanism includes a force applying mechanism capable of applying force to the first gripper, and a force transmitting mechanism that transmits force between the first gripper pair and the second gripper pair, the force applying mechanism swings the first gripper to adjust a distance between the first gripper and the second gripper, and the force transmitting mechanism transmits the force applied to the first gripper from the force applying mechanism, to the fourth gripper to swing the fourth gripper in such a manner that a distance between the third and fourth grippers (33, 34) is adjusted.