To provide automatic welding equipment and a method for an automatic welding with which an excellent automatic multi-layer welding is executed corresponding to a variation in the shape of a groove and the dispersion in the depth of the groove.

The equipment is provided with a welding head which executes a welding operation by running from the starting position of welding of a welded work to the terminal position of welding, a control device, a measurement sensor for the section shape of the groove which is provided on a welding head and measures the section shape of the groove of an welding arc at each of the running position of the welding head. The control device fetches measurement data acquired by the measurement sensor for the section shape of the groove, and is provided with an average value calculation means which calculates average values of at least the width of the groove, the laminated width of beads, the depth of the groove, and the angle of the groove in the whole running length, a layer calculation means which calculates the number of remaining layers of the welding and the height of a next laminating layer on the basis of the height of an excess welding and the height of laminated layers, a calculation means for welding condition which derives a compensation condition of measurement data of every section of a prescribed running distance of the basis of the laminating height of a next layer, the laminated width and the angle of the groove measured by the measurement sensor for the section shape of the groove, a prescribed wire speed, and a weaving-related value, and calculates a welding speed or the like on the basis of the compensation condition. A multi-layer laminating welding is executed while compensating the welding condition within the prescribed laminating height.