The invention relates to a drive device for a stop barrier or a stop or closure device with a drive unit having a drive motor (17) to which at least one single-stage step-down gear, worm gear and/or spur gear with an articulation to a pivoting crank (38) is connected, said crank being mounted on a primary shaft (46) pivoting preferably around a horizontal axis at bearing points on both sides. The shaft is provided with a fixing device (40) for the tree of the barrier(41) or barrier or closure element which can generally pivot at an angle of approximately 90° in addition to abutments for the compensation springs (48) which act upon their spring crank. The device is also provided with a single-part, single-piece drive casing (G) with open, flat securing flange strips (2) on all sides and a receiving flange (14) to secure the drive motor (17) which can be dismantled and removed. The motor shaft (36) of the drive motor is introduced into a gearbox (9) which can be closed by a lid (10) and which contains a step-down gear. An output crank (31) is fastened to the gear output shaft (30) and is hingedly connected to the pivoting crank (38) of the drive shaft (46) by means of a swivelling arm (37). The pivoting crank (38) is mounted on both sides on bearing blocks (6) which are formed on the single-piece drive casing (G) and protrudes on one side at least in the area of the bearing point in addition to being provided with a fixing device (40) for the stop or closing member or tree of the barrier (41).