Work had already started on refurbishing some stations as part of the £290million modernisation of the underground network.
Today, Strathclyde Partnership for Transport announced £776,477 would be spent at Buchanan Street.
The money will cover the contract for the design, manufacture and installation of new moving walkways – or travelators – at the station.
The work to replace the existing walkways will be carried out by Czech company Otis.
Escalators will also be renewed during the project.
SPT bosses say the moving walkways will provide a vital link to Queen Street Station, and ensure passengers continue to enjoy easy access to Buchanan Street. Work will begin next year.
SPT chairman George Redmond said: "Our ambitious, modernisation programme has offered the perfect opportunity to replace the moving walkways in Buchanan Street station.
"We are committed to keeping disruption for travellers to a minimum as we continue to deliver revitalised, modern stations that rightly keep the Subway at the heart of Glasgow."
The ageing escalators and travelators in the stations on the network have been in operation since the 1970s and are nearing the end of their life. It will take about four years before they are all replaced.
Hillhead, the first station given a major overhaul, was officially opened last month by Deputy First Minister Nicola Sturgeon.
More than £2m was spent at Hillhead on new escalators, moving the ticket office and creating retail space, new signs, better lighting and a mural by artist Alasdair Gray.
Work on upgrading Partick station is now under way, with work at Kelvinhall and Ibrox due to start next year.