An apparatus for welding the base pins of a fluorescent lamp, comprising two pairs of electrode holders disposed along the direction of advancement of said fluorescent lamp with a predetermined distance therebetween and removably holding welding electrodes, a first switch connected to the welding electrodes held by one pair of the two pairs of said electrode holders, a second switch connected to the welding electrodes held by the other pair of the two pairs of said electrode holders, and a switch control connected to the first and second switches, the apparatus being characterized in that the switching operations of the first and second switches are staggered in time by the switch control means in relation to the stepwise movement of the fluorescent lamp.