Surface acoustic wave devices and their manufacturing method

A surface acoustic wave devices comprising:

• a laminated main substrate formed by directly joining a first piezoelectric monocrystal substrate having a first polarizing direction with a second piezoelectric monocrystal substrate having a second polarizing direction opposite the first polarizing direction;
• a comb-like electrode formed on a first main surface of said main substrate;
• and
• a supplementary substrate joined to a second main surface of said main substrate, said supplementary substrate having a larger thermal expansion coefficient and a smaller thickness than said main substrate.