An ice maker has an ice-making vessel having a cylindrical shape, a cooling means, a block ice making mold which is placed inside, and an agitator. The mold includes a main mold body having a plurality of connected L-shaped plates projected radially outward from the central axis; a base plate which is joined to each L-shaped plate, and the top side of the L-shaped plates form a screw insertion part of the mold body such that the agitator fits between the L-shaped plates at a second end of the central axis.