To enable a user to safely and continuously carry out cleaning work of particularly large glass as well.

This glass cleaning method consists in moving a controller 7 along one surface of the glass to allow the controller and a magnetized cleaner 25 to follow up the other surface of the glass and washing the other surface of the glass with a washing liquid. When rising the cleaner in this method, the user washes the glass surfaces by scraping the washing liquid sticking to the glass surfaces with washing sections 31 disposed at the cleaner and removes the washing liquid after washing between the glass and the cleaner by sucking.