A method of forming a bonded body comprised of a first base member, a second base member, and a first bonding film and a second bonding film provided between the first base member and the second base member is provided. The first bonding film and the second bonding film are constituted of copper and an organic component, and an amount of copper contained in each of the first bonding film and the second bonding film is 90 atom % or higher but lower than 99 atom % at an atomic ratio. The method is comprised of: forming the first bonding film on the first base member by using a chemical vapor-film formation method; forming the second bonding film on the second base member by using a chemical vapor-film formation method; bringing the first bonding film formed on the first base member into contact with the second bonding film formed on the second base member so that the first bonding film faces the second bonding film; and applying a compressive force to the first base member and the second base member so that the first bonding film and the second bonding film are bonded together to thereby obtain the bonded body. Two base members can be firmly and efficiently bonded together with high dimensional accuracy at a low temperature, and the two base members can be efficiently separated (peeled off) to each other after use of the bonded body. Further, a bonded body is also provided.