A box opening device comprising: a plurality of first holding parts that are configured to hold a first surface, which is one of two adjacent surfaces of a folded corrugated cardboard sheet; a second holding part that is configured to hold a second surface, which is the other of the two adjacent surfaces of the corrugated cardboard sheet; and a first holding part movement mechanism which is configured to change a position of the first holding part with respect to the second holding part and thereby transforms the corrugated cardboard sheet into an opened state; wherein the first holding part movement mechanism has a link mechanism as a support member that supports the first holding part and a link mechanism drive unit connected to the link mechanism and configured to drive the link mechanism to move the first holding part by rotating the first holding part, wherein the link mechanism includes a plurality of links, each of the links being connected to another link through a joint, the plurality of links further including a first holding part attachment link that supports the plurality of first holding parts, and a driven link to which link mechanism drive unit is connected, wherein the first holding part attachment link extends in a first direction and the plurality of first holding parts are arranged on the first holding part attachment link along the first direction, and wherein the first holding part attachment link is configured to revolve while maintaining a parallel relationship between the first direction of the first holding part attachment link and the first surface; characterized in that the first holding part rotates on an arc track about a central axis of rotation (R, R') that overlaps an imaginary line extending along a boundary line between the first surface and the second surface, whereby a force only in the circumferential direction about the central axis (R, R') is applied to the first surface. a plurality of first holding parts that are configured to hold a first surface, which is one of two adjacent surfaces of a folded corrugated cardboard sheet; a second holding part that is configured to hold a second surface, which is the other of the two adjacent surfaces of the corrugated cardboard sheet; and a first holding part movement mechanism which is configured to change a position of the first holding part with respect to the second holding part and thereby transforms the corrugated cardboard sheet into an opened state; wherein the first holding part movement mechanism has a link mechanism as a support member that supports the first holding part and a link mechanism drive unit connected to the link mechanism and configured to drive the link mechanism to move the first holding part by rotating the first holding part, wherein the link mechanism includes a plurality of links, each of the links being connected to another link through a joint, the plurality of links further including a first holding part attachment link that supports the plurality of first holding parts, and a driven link to which link mechanism drive unit is connected, wherein the first holding part attachment link extends in a first direction and the plurality of first holding parts are arranged on the first holding part attachment link along the first direction, and wherein the first holding part attachment link is configured to revolve while maintaining a parallel relationship between the first direction of the first holding part attachment link and the first surface; characterized in that the first holding part rotates on an arc track about a central axis of rotation (R, R') that overlaps an imaginary line extending along a boundary line between the first surface and the second surface, wherein the first holding part movement mechanism has a link mechanism as a support member that supports the first holding part and a link mechanism drive unit connected to the link mechanism and configured to drive the link mechanism to move the first holding part by rotating the first holding part, wherein the link mechanism includes a plurality of links, each of the links being connected to another link through a joint, the plurality of links further including a first holding part attachment link that supports the plurality of first holding parts, and a driven link to which link mechanism drive unit is connected, wherein the first holding part attachment link extends in a first direction and the plurality of first holding parts are arranged on the first holding part attachment link along the first direction, and wherein the first holding part attachment link is configured to revolve while maintaining a parallel relationship between the first direction of the first holding part attachment link and the first surface; characterized in that the first holding part rotates on an arc track about a central axis of rotation (R, R') that overlaps an imaginary line extending along a boundary line between the first surface and the second surface, whereby a force only in the circumferential direction about the central axis (R, R') is applied to the first surface.