An acoustic lens disposed in front of a speaker or the like and changing the travelling direction of a sound wave, wherein a plurality of fins (1) are arranged in parallel with one another and inclined at a predetermined angle ( theta 1) with respect to the travelling direction (A) of the sound wave. The length of each fin (1) is varied so that the lengths of sound paths (2) defined between associated adjacent fins (1) become progressively shorter from one of the ends to the other of the reference plane (B) existing in a direction orthogonal to the travelling direction (A) of the sound wave, or the length of each fin (1) is varied so that the lengths of the sound paths (2) become progressively shorter from one of the ends to an intermediate portion of the reference plane but the lengths of the ramaining fins (1) are made uniform so that the lengths of the remaining sound paths (2) are equal from the intermediate portion to the other end. In this manner, the arrival plane (D) of the sound wave can be inclined either completely or only partially at a predetermined angle ( theta 3) in one desired direction and directivity in only desired direction can be improved.
