To provide a mobile scaffolding work platform applicable as footing for external wall work execution that needs no connection with external building walls in the construction of higher stories of a high-rise steel structural building.

The mobile work platform used for the construction of higher stories of a high-rise building has a story scaffolding work platform a consisting of plural scaffolding work platforms or footings 3 for each floor work execution provided with motor-operated carriage driving wheels 4 so that the story scaffolding work platform a may move on a rail 2 laid along building wall iron frames 1, a laterally protruding frame arm stay 5 is fixed on the iron-frame wall surface for the highest scaffolding work platform 3a of the story scaffolding work platform a, a motor-driven reserve guide wheel 6 is provided just below the other end of the frame arm stay 5, and the reserve guide wheel 6 is provided with an engagement lug 7 for sliding engagement with a roof rail 8 laid on the roof of the building steel structural frames, so that no connection with building walls may be necessary for the movements of mobile story scaffolding work platform a.