PURPOSE: To provide a method to perform the alignment of a part where video read by a manual operating type image scanner 10 are overlapped.

CONSTITUTION: Two sets of video -Y1, +Y2 read in by an image scanner are overlapped partially, and they are displayed on a display part. At this time, aberration occurs, therefore, A1 of -Y1 and B1 of +Y2 are selected and instructed at one terminal part as a first point where they should coincide with each other. Those are displayed by superimposing, and the amount of travel between A1 and B1 at the first point is decided. A2 of the inverse of Y1 and B2 of +Y2 are selected and instructed at another terminal part as a second point where they should coincide with each other, and they are displayed by superimposing, then, the amount of travel between A2 and B2 at the second point is decided. An angle θ of rotation at which +Y2 should be moved is decided from the amount of travel at the first and second points, and the parallel displacement of +Y2 is performed so as to obtain relation A1=B1. Thence, the angle θ of rotation is rotated centering about a point A1=B1. Thereby, both images can coincide with each other, and they can be synthesized.