A portable water purifier according to the present invention includes: a container that is open at least at the top and has a predetermined internal volume; a cap that is coupled to the top of the container to seal the container and has an exit for selectively communicating with the container; a pump that is embedded in a side of the container and supplies air in a predetermined direction into the container; and a filter assembly that is coupled to the bottom of the cap and inserted in the container to filter water. According to the present invention, it is possible to simply supply purified water using pressure from the pump embedded in a side of the container to supply air into the container in a predetermined direction.