Noppadol Permpittaya said the extension would help Bangkokians to use the service after their work.
He said city residents can also use the service during their lunch breaks.
Currently BMA pawnshops are opened from 8am to 4pm.
The extended hours will be piloted at four branches starting on December 1 – the Thewes pawnshop, Min Buri pawnshop, Pradipat pawnshop and Wong Wien Lek pawnshop.
If successful, the extension time will be applied to all 21 branches, Noppadol added.