Abstract: A cable holder, a magnetic ring fixing device, and an air conditioner outdoor unit. The cable holder includes a holder body; cable grooves running through a side of the holder body are provided in the holder body; two side groove walls of each cable groove are respectively connected to first clamping arms towards the bottom of the groove at an opening; the distance between the two first clamping arms gradually decreases from the opening of each cable groove to the bottom of the groove; a fixing groove for matching a cable is provided at the bottom of each cable groove. Thus, cables can be conveniently placed in the cable grooves, and the cables cannot easily pass out of the cable grooves; moreover, by arranging the fixing grooves, the cables can be fixed and limited, offset movement of the cables can be reduced, and an anti-falling effect can be better realized.