Recently, repair or strengthening of steel members by bonding CFRP plates has been widely reported, and the design method to prevent the debonding of CFRP plates were proposed in overseas. In Japan, however, debonding-prevention-design for CFRP plate bonded steel members have not been specified. In this research, to clarify the effect of loading conditions on the adhesive stresses of steel members strengthened by bonding CFRP plates, shear and normal stresses in adhesive at CFRP plate ends were derived under the conditions of pure bending moment, concentrated load and uniformly distributed load. Furthermore, estimation equations of shear and normal stresses in adhesive at the end of CFRP plate under several loading conditions were given.