The invention provides a cup placing device. The device comprises a mounting frame, a cup holder, two guide rails, a separator, a driving device and a position sensor, wherein a through hole is formed in the mounting frame, the cup holder is fixed on the mounting frame, and the two guide rails are fixed on the mounting frame and positioned on both sides of the through hole; both side edges of the separator are positioned in the two guide rails and slide in the guide rails, and an edge of a medicine cup is supported on the separator; the driving device is fixed on the mounting frame, and the position sensor is arranged on the mounting frame; a first through groove is formed in the front end of a supporting plate of the separator, and a dropping hole is formed in the rear end of the supporting plate of the separator; and a separating plate of the separator is fixed on the supporting plate, a second through groove is formed in the separating plate, and isolation grooves are also formed in the front end of the separating plate. For the cup placing device disclosed by the invention, the separator is driven by the driving device to move forward and backward in a straight line, so that the medicine cup is separated; and through the use of the device disclosed by the invention, the process of separating the medicine cup is fully automated, so that the efficiency of separating the medicine cup is improved, the manufacturing cost of a product is reduced, and the pollution to the medicine cup from a hand is also effectively avoided.