An apparatus for supplying drinking water comprising a container (1) in which drinking water such as natural water or tap water is accommodated and which is arranged detachably; a water cooler (22) which cools drinking water supplied from the container (1); a sterilizer (5) which is installed in the water cooler (22) and sterilizes drinking water in the water cooler (22); a cold water valve (23) which controls supplying operation and stopping operation for drinking water in the water cooler (22); and a container detector (4) which detects whether or not the container (1) has been detached, wherein, after the container detector (4) has detected a state in which the container (1) has been detached, drives the sterilizer (5) for a predetermined period. This enables bacteria having invaded into the container (1) to be killed in a well-timed way.