The shocking accident, which occurred at the Jakarta Stock Exchange yesterday, left at least 70 people injured and forced a chaotic evacuation.
At the time it collapsed, the mezzanine floor was carrying around 40 visiting students who can be seen hurtling towards the ground as the floor gives way.
MetroTV footage showed the lobby below strewn with debris afterwards and people being carried away on stretchers.
A Jakarta police spokesman said the collapse was an accident and not the result of an explosion.
'We are still investigating the cause, but for now our priorities are the casualties,' Jakarta police spokesman, Argo Yuwono, told Metro TV.
It was not immediately clear what had caused the collapse, but a building expert told local TV stations that 'material degradation' could be to blame.