A vehicle door glass elevating/lowering device performs elevating/lowering operation of window glass by a driving force of a drive source along a sash member along one of front and rear edges of the window glass in a door sash forming a window opening. The glass elevating/lowering device includes: a guide rail on the sash member; a slider having a glass support secured to the glass and a sliding part guided movably in the elevating/lowering directions with respect to the guide rail; and a transmission member that transmits the driving force of the drive source, in which a first sliding part regulated in position by the guide rail in at least one direction of the vehicle front-rear directions and a second sliding part regulated in position by the guide rail in at least the other direction of the vehicle front-rear directions are provided at mutually different positions in the elevating/lowering directions.