The present invention relates to a cold air guide structure of an ice-making chamber of a cold chamber door. The structure including: the cold chamber door; an insulation case disposed inside of the cold chamber door, thermally insulated and having an ice-making chamber therein; an ice-making unit installed in the ice-making chamber of the insulation case, for icing a supplied water by an ice-making cold air and housing pieces of ice; an insulation cover for opening and closing the ice-making chamber of the insulation case; a cold air inlet port for sucking the ice-making cold air into the ice-making chamber; a cold air outlet port for exhausting the ice-making cold air from the ice-making chamber; and an ice-making cold air guide unit for guiding the ice-making cold air to a predetermined air passage to suck or exhaust the ice-making cold air into or from the ice-making chamber.