A dressing device for dressing a grinding stone is disclosed. The grinding stone is used for grinding an edge of a glass pane. The dressing device comprises a container in which dressing members are contained and piled. A grooved holding member mounts thereon the container. The holding member includes a front portion projected forward from a front wall of the container and a rear portion projected rearward from a rear wall of the container. The front and rear walls of the container are respectively formed with front and rear openings whose lower peripheries are bounded by a bottom wall of the groove of the grooved holding member. The front opening is so sized to pass therethrough each of the dressing members. A pushing plate is slidably received in the groove of the rear portion of the holding member. The pushing plate is so sized so as to pass through the rear opening. The hydraulically oprated cylinder moves reciprocatively the pushing plate in the along the groove between a position wherein a forward end of the pushing plate is deeply inserted into the container through the rear opening and another position wherein the forward end is drawn away from the container.