To weld the titanium clad steel plate not causing lowering of joining strength near a weld zone due to an embrittling layer at a joining boundary face, deterioration in corrosion resistance in a weld zone between a clad material and a spacer, lowering of corrosion resistance due to turbulent flow generated with a strap, etc.

By removing a clad material 2 near a butt welding part, base metals are subjected to butt welding, successively, by inserting a spacer 3 to the part where the clad material is removed, the welding between the edge face of a spacer 3 and an edge face of the butting material is conducted under the condition satisfying the following. t>V(v)×I(A)×60/v(cm/min)/10000>0.5, here, (t): thickness of clad material, V: welding current, I: welding current, (v): welding speed.