To provide a butting method which prevents shear drop generated on a cut end surface when a thick steel plate is cut by a shear so as to obtain a satisfactory cut end surface.

When a thick steel plate is cut by the use of a shear, notches having constant depth such as a V-shaped groove, are formed on the inside and outside surfaces of the steel plate along a cutting line so that stress concentration at the time of cutting is easily generated. Further, a range from 30 to 50mm where is a side opposite to a cutting edge from these notches is cooled to generate a temperature difference of 50-150°C from the other part so that the deformation resistance of a drop generating part is increased.