A connection method for a terminal fitting, in which the terminal fitting includes a terminal body and a plurality of terminal connection portions extending from the terminal body, and a pair of fastening caulking pieces of each of connection terminals connected to end portions of electric wires are caulked and connected to a pair of fastened caulking pieces formed in a corresponding one of the terminal connection portions, the connection method includes folding open end portions of the fastened caulking pieces inward respectively to form folded portions and a space between the folded portions so that open end portions of the pair of fastening caulking portions enter the space, and crushing the pair of the fastening caulking pieces to caulk the pair of the fastened caulking pieces so that the open end portions of the pair of the fastening caulking pieces enter the space.