An automatic dispensing apparatus (10) can switch a switcher (31) to a first mode to dispense a plant culture medium to a filling device (40) through a feeding tube (32,33) and a discharging tube (34) from a storage tank (20). In the meantime, the filling device (40) can fill a culture container (12) with the plant culture medium and then a conveying platform (60) can convey the culture container (12) containing the plant culture medium to an accommodating platform (57). Next, the switcher (31) is switched to a second mode, a cleaning fluid is infused into the feeding tube (32,33) to pass therethrough and exhaust through a waste exhaust tube (35). Thus, the automatic dispensing apparatus (10) can function as sterilization and cleaning to reduce the labor cost, boost the operational efficiency, and enhance the filling stability.
