Effect of liner laser irradiation on bending properties of thin high carbon steel plate was investigated in this study. Laser-transformed zone included solidification structure and quenched zone by laser irradiation was observed in cross section area of specimen by double-etching. Shape of laser-transformed zone changed significantly with changing of heat input. Deformation after laser irradiation occurred by the excess of heat input. Average area ratio of laser-transformed zone for normal bending specimen without deformation was cleared at each thickness. Sensitivity for laser deformation increased with decreasing of thickness. Three points bending test was executed to obtain Flexural load-deflection curve. Bending property of thin steel plate improved by laser liner irradiation and flexural load per unit deflection increased by suitable laser irradiation condition. Absorb energy of bending test also increased by existence of laser-transformed zone.