To evenly wash the whole circumference of the outer periphery of a mouth part of a container while enhancing washing efficiency in an apparatus for washing the outer periphery of the mouth part of the container.

The apparatus for washing the outer periphery of the mouth part of the container 1 includes a washing nozzle 32 facing the outer periphery of the mouth part 1B of the container 1, and a rotation device 40 allowing the washing nozzle 32 and the mouth part 1B of the container 1 to be relatively rotated around a center shaft of the mouth part 1B of the container 1.