A pressing tool for bone surgery, comprising: a pressing member formed in a columnar shape shaft along a longitudinal axis having, at one end, a pressing surface formed of a convex and spherical surface and a male thread extending from the pressing surface in a longitudinal direction; and a hook member that has a curved portion being curved to form a hook shape configured to cover half around a side surface of a bone and to engage with the side surface of the bone, the hook member having a cylindrical support portion provided at a first end of the curved portion configured to support the pressing member so that the pressing surface is directed toward a second end of the curved portion, the hook member having a projection portion at the second end, the projection portion projecting toward the support portion and being configured to bite into the side surface of the bone, wherein the support portion has a screw hole extending in the longitudinal direction and supports the pressing member in state of the pressing member is movable in the longitudinal direction toward the projection portion by the male thread being fastened to the screw hole, wherein the support portion has a slit that extends from an outer circumferential surface to an inner circumferential surface of the support portion so that an interior of the screw hole communicates with an exterior of the support portion in a radial direction of the screw hole, the slit being formed throughout an entire length of the support portion in the longitudinal direction, and wherein a guide pin is inserted into the support portion in the radial direction through the slit. a pressing member formed in a columnar shape shaft along a longitudinal axis having, at one end, a pressing surface formed of a convex and spherical surface and a male thread extending from the pressing surface in a longitudinal direction; and a hook member that has a curved portion being curved to form a hook shape configured to cover half around a side surface of a bone and to engage with the side surface of the bone, the hook member having a cylindrical support portion provided at a first end of the curved portion configured to support the pressing member so that the pressing surface is directed toward a second end of the curved portion, the hook member having a projection portion at the second end, the projection portion projecting toward the support portion and being configured to bite into the side surface of the bone, wherein the support portion has a screw hole extending in the longitudinal direction and supports the pressing member in state of the pressing member is movable in the longitudinal direction toward the projection portion by the male thread being fastened to the screw hole, wherein the support portion has a slit that extends from an outer circumferential surface to an inner circumferential surface of the support portion so that an interior of the screw hole communicates with an exterior of the support portion in a radial direction of the screw hole, the slit being formed throughout an entire length of the support portion in the longitudinal direction, and wherein a guide pin is inserted into the support portion in the radial direction through the slit.