An optical module includes an optical fiber array and a lens array. An optical signal is mutually transmitted between the optical fiber array and the lens array. The optical fiber array and the lens array are secured to each other in a state in which the optical fiber array and the lens array are aligned with each other. An optical path is formed between the optical fiber array and the lens array to permit the optical signal through. A hollow spacer is located between opposing surfaces of the optical fiber array and the lens array. A hollow portion is formed in the hollow spacer. The size of the hollow portion is large enough so that the hollow spacer does not interrupt the optical path. The hollow spacer is adhered to the optical fiber array and the lens array to secure the optical fiber array and the lens array.