In a semiconductor laser array in which a semiconductor laser element having a horizontal-direction cavity, and plural outer inclined reflecting mirrors capable of reflecting laser light projected from the semiconductor laser element along a specific direction are integrated on a semiconductor substrate in a monolithic form, these outer inclined reflecting mirrors are positioned adjacent to each other, and also are arranged in such a manner that a distance between the adjoining horizontal-direction cavities becomes longer while being located apart from said outer inclined reflecting mirrors.