Abstract: A method of joining a first electroconductive plate member made of metal to a second electroconductive plate member made of metal dissimilar to the metal for the first plate member by the use of at least one anchor peg made of the same metal as the second plate member. The first and second plate members are initially overlapped one above the other to provide a plate assembly which is subsequently clamped under pressure between welding electrodes with the anchor peg positioned between one of the welding electrodes and the first plate member. Thereafter, an electric current is supplied to the welding electrodes to initially cause a portion of the first plate member held in contact with the anchor peg to melt by resistance-heating of the anchor peg to thereby allow the anchor peg to be pierced through the first plate member and then to cause the anchor peg extending completely across a thickness of the first plate member to be welded to the second plate member.