The present invention relates to a high-density ethylene-based polymer comprising an ethylene homopolymer or a copolymer of ethylene and at least one comonomer selected from the group consisting of an α-olefin, a cyclic olefin, and a straight, branched and cyclic diene. According to the present invention, the high-density polyethylene resin has a wide molecular weight distribution and excellent comonomer distribution characteristics, has excellent melt flowability due to a long chain branched structure, and has excellent mechanical characteristics since the comonomer distribution is concentrated in a high-molecular-weight body. The high-density ethylene polymer of the present invention has excellent molding processability during processing such as extrusion, compression, injection and rotational molding by having excellent mechanical characteristics and melt flowability.