High strength dual-phase stainless steel sheet and steel strip which are excellent in corrosion resistance, the dual-phase stainless steel sheet and steel strip having a Vicker's hardness of 200HV or more and comprising, by mass %, C: 0.02 to 0.20%, Si: 0.10 to 2.0%, Mn: 0.20 to 2.0%, P: 0.040% or less, S: 0.010% or less, Cr: 15.0 to 18.0%, Ni: 0.5 to 4.0%, Sn: 0.05 to 0.50, N: 0.010 to 0.10%, and a balance of Fe and unavoidable impurities. The dual-phase stainless steel sheet and steel strip have a γp range of 60 to 95, and a ferrite and martensite dual-phase microstructure formed by being heated to the ferrite and austenite dual-phase region, then the austenite phase transforming to martenite in the subsequent cooling process, wherein γp=420C+470N+23Ni+7Mn+9Cu−11.5Cr−11.5Si−12Mo−7Sn−49Ti−47Nb−52Al+189.