A rotating structure of a rotary member having a predetermined width and suitable for being disposed in a press molding apparatus comprising: the rotary member; a main body positioned under the rotary member; and a rotating block to be attached to the rotary member and the main body, characterized in that: the rotating block includes a convex strip to be attached to the lower portion of the rotary member and a concave strip to be attached to the main body, the convex strip includes a flat mounting portion and a convex sliding portion, and is formed with bolt holes penetrating through the mounting portion and the convex sliding portion at a plurality of positions, the concave strip includes a flat mounting portion and a concave sliding portion, and is formed with bolt holes penetrating through the mounting portion and the concave sliding portion at a plurality of positions, the convex sliding portion and the concave sliding portion are positioned at slidable positions, projecting portions are provided at both ends (22a, 22a) of the rotary member in the width direction at positions lower than the axial center position of the rotary member, and arcuate shaped drop preventing holding portions corresponding to the trajectory of rotation of the rotary member are disposed for the projecting portions, so that edge portions of the projecting portions move along edge portions of the drop preventing holding portions in association with the rotation of the rotary member. the rotary member; a main body positioned under the rotary member; and a rotating block to be attached to the rotary member and the main body, characterized in that: the rotating block includes a convex strip to be attached to the lower portion of the rotary member and a concave strip to be attached to the main body, the convex strip includes a flat mounting portion and a convex sliding portion, and is formed with bolt holes penetrating through the mounting portion and the convex sliding portion at a plurality of positions, the concave strip includes a flat mounting portion and a concave sliding portion, and is formed with bolt holes penetrating through the mounting portion and the concave sliding portion at a plurality of positions, the convex sliding portion and the concave sliding portion are positioned at slidable positions, projecting portions are provided at both ends (22a, 22a) of the rotary member in the width direction at positions lower than the axial center position of the rotary member, and arcuate shaped drop preventing holding portions corresponding to the trajectory of rotation of the rotary member are disposed for the projecting portions, so that edge portions of the projecting portions move along edge portions of the drop preventing holding portions in association with the rotation of the rotary member. the rotating block includes a convex strip to be attached to the lower portion of the rotary member and a concave strip to be attached to the main body, the convex strip includes a flat mounting portion and a convex sliding portion, and is formed with bolt holes penetrating through the mounting portion and the convex sliding portion at a plurality of positions, the concave strip includes a flat mounting portion and a concave sliding portion, and is formed with bolt holes penetrating through the mounting portion and the concave sliding portion at a plurality of positions, the convex sliding portion and the concave sliding portion are positioned at slidable positions, projecting portions are provided at both ends (22a, 22a) of the rotary member in the width direction at positions lower than the axial center position of the rotary member, and arcuate shaped drop preventing holding portions corresponding to the trajectory of rotation of the rotary member are disposed for the projecting portions, so that edge portions of the projecting portions move along edge portions of the drop preventing holding portions in association with the rotation of the rotary member.