A joint structure includes: a plurality of holes open to opposing surfaces of two members that oppose to each other, the holes each being filled with a fluid or powder filler (U) in a state where the holes communicate with each other, such that the two members are relatively fixed by the filler. The holes of the two members each have an inner surface that is wider in cross-sectional direction at a location distant from openings of the holes than at a location close to the openings.