A magnetron cooling fin is disclosed, characterized in that a plurality of turbulence-promoting protrusions are provided on one side of a planar body that has a boss-type through-hole in which an anode is coupled and a plurality of coupling pieces outwardly extending and bent at edges of the planar body, whereby, with inflow air undergoing flow separation at top ends of the turbulence-promoting protrusions and coming again into contact with the planar body, an existing temperature boundary gets thinned and a friction coefficient gets increased, thereby improving a heat transfer rate and an cooling efficiency.