In an optical apparatus according to the present invention, the lens thicknesses and curvature radiuses of respective first lenses are optimized so that beam waist positions of optical beams emitted from the respective first lenses of a lens array are independently changed according to aberration of a second lens, and the focal position deviation due to the aberration of the second lens is cancelled by a difference between the beam waist positions, which is given on the lens array side. As a result, it is possible to suppress, at a low cost, variations in focal positions of the optical beams which are emitted from respective ports of the lens array to be condensed by the common lens.