An acoustic wave device applicable to a wider scope and field and used for transporting a substance of any of wide variety of types to be transported with an improved efficiency without needing to clean a piezoelectric substrate and simultaneously transporting two or more physically separated substances along the propagation direction of a surface acoustic wave. An acoustic wave device has an exciting electrode for exciting a surface acoustic wave formed on a piezoelectric substrate generating a surface acoustic wave by a piezoelectric effect. A transport path plate is disposed adjacently to the exciting electrode over the piezoelectric substrate with a water layer (W) interposed therebetween. When current is supplied to the exciting electrode, a surface acoustic wave is generated on the piezoelectric substrate. The surface acoustic wave causes a longitudinal wave to be emitted into the water layer (W) and attenuates. The emitted longitudinal wave is propagated to the transport path plate, and a droplet (Dp) placed on the transport path plate is displaced by the emission pressure.