An apparatus for forming electrical solder connections in a disk drive unit includes: a nozzle device for carrying out soldering on two pre-welding surfaces; a solder ball feeding device for transferring a single solder ball to the nozzle device; a gas pump device for supplying pressurized gases to the nozzle device; a laser device for emitting laser beams to the solder ball; and a control device including at least one sensor for at least detecting status of the solder ball or pressure in the nozzle device or distance between the nozzle device and the pre-welding surfaces, and a control unit connected with the at least one sensor. The present invention can easily control the solder ball, the pressurized gases and the laser beams, thereby keeping the pressure of the nozzle device and the laser energy stable and, in turn improving the soldering result.