To provide an arc start method in a consumable electrode type arc welding method capable of firmly executing arc start and capable of executing high quality high speed welding by restraining a welding defect from being brought about therefor, at a portion of a wire projected from a welding tip, a temperature of a front end portion of the wire is made to be at a temperature higher than a temperature of a portion thereof near the welding tip. The front end portion of the wire is preheated to 300° C. or higher, preferably, 450° C. or higher. The front end portion of the wire is preheated by generating arc for preheating. The preheating arc is generated in a spot-like shape at a position near a terminal end portion of a predetermined welding line by constituting a current lower than a welding current.