Abstract: A welding machine, preferably of the flash butt welding type, designed to facilitate maintenance of the clamping means, e.g. clamps, of the two longitudinal metal products to be welded. Advantageously, a first structure, provided with first clamping means, and a second structure, provided with second clamping means, are supported in a first part of the carriage delimited by a first beam and a second beam of the carriage parallel to the feeding direction, while at least one transformer is fixed to the carriage and supported in a second part of the carriage, arranged laterally outside the first part.