The invention provides a
welding robot which makes it possible to, in a seam tracking operation during tandem
welding, realize a high tracking ability, not only for a leading
electrode, but also for a trailed
electrode. A translational correction calculating unit (23) corrects a target value Plead(t) of the leading
electrode (5a) using a translational correction amount
Delta P(t) in a base coordinate
system Sigmabase for a next time position of the leading electrode (5a), to obtain a primary correction target value Plead(t)'. A rotational correction calculating unit (24) calculates a rotation correction amount
Delta theta(t) for correcting displacement of an orientation of a
torch (6) around the leading electrode (5a) with respect to a actual
weld line Lre generated because of the translational correction amount
Delta P(t), and calculates a secondary correction target value Plead(t)'' resulting from correcting the primary correction target value Plead(t)' so that the
torch (6) rotates around the leading electrode (5a) by the rotation correction amount Delta theta(t). A
manipulator (2) is driven on the basis of the secondary correction target value Plead(t)''.