Joint structure, joint body, and member set

A joint structure comprising:

• a first joint part formed in a first member and a second joint part formed in a second member that are fitted and fixed together wherein at least either of the first member and the second member is made of an elastic fiber reinforced plastic (FRP) member that contains reinforcing fibers with an average fiber length of 1 mm or more;
• wherein the reinforcing fibers are dispersed in a web-like manner so that reinforcing fibers are adhered together with resin at at least part of their intersections, and that contains voids in an amount in the range of 20 vol % or more and 95 vol % or less;
• wherein the first joint part has a recessed shape in at least one cross-section of the joint structure while the second joint part has a shape that fits into the recessed shape of the first joint part in that cross-section;
• and
• wherein a pressing force exists between the first joint part and the second joint part so that the first member and the second member are fitted and fixed together.