A surface acoustic wave (“SAW”) sensor includes; a first signal generator which generates a first signal having a predetermined frequency bandwidth using a pseudo random sequence, a second signal generator which generates a second signal with a predetermined frequency, a signal blender which blends the first signal with the second signal to generate a blended signal having the predetermined frequency bandwidth with the predetermined frequency as a center frequency, a wave generator which generates a surface acoustic wave using the blended signal, which converts the surface acoustic wave into a third signal after the surface acoustic wave travels a predetermined distance, and which outputs the third signal, and a signal detector which detects a change in the third signal from the wave generator to sense a substance bound to the wave generator.