Method of welding dissimilar metal materials and welded body of dissimilar metal materials

A method of welding dissimilar metal materials, comprising:

• preparing a rotatable tool;
• positioning a high melting-point material and a low melting-point material which are dissimilar metal materials having melting points different from each other to a planned welding position;
• pressing the rotatable tool to the high melting-point material and then inserting the rotatable tool thereinto while rotating the rotatable tool;
• and
• performing a friction-stir-welding between the high melting-point material and the low melting-point material to each other,
• wherein the friction-stir-welding between the high melting-point material and the low melting-point material is performed by disposing an intervening piece made from a same material as the high melting-point material between the rotatable tool and the high melting-point material.