A surface acoustic wave device of low insertion loss is provided whose transfer function in its passband is improved. Pairs of electrode fingers form a first group of split electrodes (5a1, 5b1, 5a2, 5b2, 5a3, 5b3,...). Pairs of electrode fingers form a second group of split electrodes (6a1, 6b1, 6a2, 6b2, 6a3, 6b3,...). Each pair of electrode fingers in one group is interleaved with the corresponding pair of electrode fingers in the other group. Each pair of electrode fingers includes an electrode finger narrower than λ / 8 (where λ is the wavelength of a surface acoustic wave at center frequency) and an electrode finger wider than λ/8, and the distance between the centers of adjacent electrode fingers is not λ/4.