The existing 440,000 sq ft shopping centre will be demolished to pave the way for 464 homes across several blocks, a hotel and new market building.
Appointed contractor, BCEGI has started work on site commencing with the demolition of the car park bridge.
The work is due to take 18 months in total, however, during this time once areas of the site have been demolished, new development phases will commence.
The first of these phases is the New Market Hall, which is due to be delivered by 2024.
Planning for the redevelopment of the Galleries shopping centre was granted a year ago.
Warren Taylor, director of Cityheart, said: “We are fully committed to delivering this important scheme and continue to work alongside Wigan Council and local community to achieve our vision. It is exciting to see the first stage of the transformation taking place, together with the new hoardings that have been erected, it really feels like tangible progress is being made.”