Using the plain specimen and U-notched specimen which were made from the butt joint welded between high tensile steel (HT 60) and mild steel (SM 41), static tensile tests were carried out in the direction of weld line. The distributions of elastic and plastic strain on the specimens, were experimentally analyzed by strain gage and Moire method at successive stages of loading. The following characteristics were clarified on the strain behaviors of welded joint between two dissimilar steels in comparison with those of base metals. 1) Ultimate tensile strength of the welded joint between two dissimilar steels is about the average value of that of HT 60 and SM 41. However, the elongations of welded joint up to the maximum tensile load and to the fracture are larger than those of HT 60 and approach to SM 41. 2) While in HT 60 the localization of strain is remarkable at the position of fracture initiation, the strain on HT 60 side of the welded joint between two dissimilar steels does not concentrate so greatly as HT 60 and increases at the regions far from the fracture initiation as much as on SM 41 side of welded joint. 3) In the welded joint between two dissimilar steels, the remarkable strain concentration is induced on HT 60 side after the maximum tensile load is reached and then the joint cracks on that same side. 4) While the fracture of HT 60 shows the double shear type, that of SM 41 is of the single shear type. Then the double shear crack generated on HT 60 side of the welded joint between two dissimilar steels exchanges for single shear one on SM 41 side.