In a multi-electrode welding torch, electrodes (2) are configured into a shape that has an arc-shaped curved surface area (R) in at least a portion of a cross-section thereof that is orthogonal to the longitudinal direction thereof. Collets (4) are each provided with a groove portion (4a) in which an electrode (2) is fitted, and whose inner wall surfaces (4b) come into contact in a plurality of locations with the curved surface area (R) when viewed in the longitudinal direction of the electrode (2).