Waves caused by steady ship motion are analyzed by the finite element method on the basis of the concept of the superposition of analytical and finite element solutions. The radiation condition is substituted by assuming appropriate radiating waves. Wave motions in a certain domain Ω^a around the ship is assumed as a linear combination of the radiating waves and certain finite element solutions. The amplitude of the radiating waves can be determined by the condition of continuity on the surface of the domain Ω^a, which can be expressed as the form of a single collocation equation. The finite element formulation can be developed by the same way as linear elastic problems, and its analysis can be performed easily by the use of general-purpose-programs for structural analysis. Numerical results obtained by the present method is compared with those by the previous authors, and they show good agreement.