An outdoor unit bracket for supporting an outdoor unit of an air conditioner, being installed on an outer wall of a building, comprising: an outer wall coupling portion for coupling to the outer wall of the building; an upper supporting portion for coupling to a rear upper portion of the outdoor unit, being spaced apart from the outer wall coupling portion in the direction vertical to the outer wall of the building; an outer wall contacting portion for contacting the outer wall of the building by the self-weight of the outdoor unit, being spaced apart from the outer wall coupling portion below the outer wall coupling portion; and a lower supporting portion for contacting a rear lower portion of the outdoor unit by the self-weight of the outdoor unit, being spaced apart from the outer wall contacting portion in the direction vertical to the outer wall of the building; and a middle connecting portion disposed between the outer wall coupling portion and the outer wall contacting portion, wherein the outer wall coupling portion has an anchor bolt hole through which an anchor bolt, for coupling the outer wall coupling portion to the outer wall of the building, passes, wherein an upper side of the upper supporting portion is bent toward the outer wall coupling portion in order that a flange at the rear upper portion of the outdoor unit can slide along the upper supporting portion, wherein both ends of the lower supporting portion are bent toward the outer wall contacting portion in order that the outdoor unit can be slidingly coupled to the upper supporting portion, wherein the middle connecting portion does not contact the outer wall of the building when the outer wall contacting portion contacts to the outer wall of the building. an outer wall coupling portion for coupling to the outer wall of the building; an upper supporting portion for coupling to a rear upper portion of the outdoor unit, being spaced apart from the outer wall coupling portion in the direction vertical to the outer wall of the building; an outer wall contacting portion for contacting the outer wall of the building by the self-weight of the outdoor unit, being spaced apart from the outer wall coupling portion below the outer wall coupling portion; and a lower supporting portion for contacting a rear lower portion of the outdoor unit by the self-weight of the outdoor unit, being spaced apart from the outer wall contacting portion in the direction vertical to the outer wall of the building; and a middle connecting portion disposed between the outer wall coupling portion and the outer wall contacting portion, wherein the outer wall coupling portion has an anchor bolt hole through which an anchor bolt, for coupling the outer wall coupling portion to the outer wall of the building, passes, wherein an upper side of the upper supporting portion is bent toward the outer wall coupling portion in order that a flange at the rear upper portion of the outdoor unit can slide along the upper supporting portion, wherein both ends of the lower supporting portion are bent toward the outer wall contacting portion in order that the outdoor unit can be slidingly coupled to the upper supporting portion, wherein the middle connecting portion does not contact the outer wall of the building when the outer wall contacting portion contacts to the outer wall of the building.