The present invention relates an automatic vacuum cleaner. According to an aspect of the present invention, the automatic vacuum cleaner includes a first movement part and a second movement part capable of together moving along an inclined cleaning surface, a movement unit provided in at least one of the first movement part and the second movement part, a cleaning member provided in at least one of the first movement part and the second movement part, and a detection unit which detects states of the cleaning surface, wherein movement speeds of the first movement part and the second movement part are varied according to the sates of the cleaning surface.