A joined body includes a first member, a second member, and a joining portion disposed therebetween and joining the first member and the second member. The joining portion includes a first joining layer on a side toward the first member and formed of a first joining material, a second joining layer on a side toward the second member and formed of a second joining material, and a metal layer therebetween and having a plurality of holes communicating with one another. The metal layer includes a first-joining-material-impregnated layer on a side toward the first joining layer and in which the plurality of holes are impregnated with the first joining material, a second-joining-material-impregnated layer on a side toward the second joining layer and in which the plurality of holes are impregnated with the second joining material, and an unfilled hole layer therebetween and in which the plurality of holes are void.