The suspects approached the guard hut where three of the suspects, armed with pistols, held up two security guards.
Capt Johannes Ramphora, Springs police spokesman, says the suspects ordered the guards to hand over the keys to the office.
Seven of the suspects left the guard room to open the offices in the building.
Ramphora says the suspects helped themselves to computers, laptops, a microwave, a camera, a drill machine and a jigsaw.
The 10 suspects left the premises with the stolen goods without firing a shot.
Ramphora says the guards waited a while to make sure that the suspects had left and then called for help.
The police arrived at the scene shortly after the robbery, took statements from the two guards and opened a case of business robbery.
