Bag body and method for producing bag body

A bag body comprising a bag material including a bottom portion and an opening portion, wherein a lifting rope is provided around the opening portion, a restraining rope that is pulled out through the opening portion is provided at the bottom portion,

• the bag material is filled with a filling material to form the bag body,
• the opening portion is closed after the bag material is filled with the filling material, and
• the bag body is within a predetermined range centered about a curve given by W/H1 (diameter/restraining rope length)=15.898×(W/W0){circumflex over ( )}2−17.784×(W/W0)+6.6314,
• where W represents a diameter of the bag body, H1 represents a length of the restraining rope from the bottom portion of the bag body to a root position of a mouth closing rope of the bag material through a center of the bag body, and W0 represents a diameter of the bag body when the bag body formed by filling the bag material with the filling material is most stable against waves.