Starting from the Kirchhoff diffraction integral formulation (1) or (2), the complex amplitude distribution (18) ~ (21) in the image of a point object is given with an approximation of excelling the Fresnel diffraction field. The new formula is derived by means of the wavefront surface generating 'the diffraction to the image plane and not introducing the reference sphere. The changing part 3 of the distance r is expanded into the form (6). The (l + cosa)/r is expanded into the form (7) or (10), (11) and (12). The slant (13) of the wavefront surface toward the image plane is also investigated. The wave aberration W is defined by a new form (5) or (25). It is convenient in computing to the formula (25). In order that the amplitude distribution becomes an obvious model, the new variable y and z are quoted. There is the relation (15) between the exit pupil coordinates y, z and them. Therefore, the amplitude distribution in the image of a point object is obtained by adding the three Fourier transform(22), further.