An ethylene (co)polymer of the present invention is a (co)polymer with excellent moldability and mechanical properties and either an ethylene homopolymer or a copolymer of ethylene and an α-olefin of 4 to 20 carbon atoms. The (co)polymer has methyl branches measured by 13C-NMR less than 0.1 in number per 1,000 carbon atoms and Mw/Mn measured by GPC not lower than 1.8 and lower than 4.5. The (co)polymer is either an ethylene homopolymer or a copolymer of ethylene and an α-olefin of 3 to 20 carbon atoms. The melt tension (MT) and the swell ratio (SR) satisfy the relation; log(MT)>12.9−7.15×SR; and the intrinsic viscosity ([η]) and the melt flow rate (MFR) satisfy the relation; [η]>1.85×MFR−0.192 in the case of MFR 1.85×MFR−0.213 in the case of MFR≧1. Such an ethylene (co)polymer can be usable for various molding applications and especially suitable for pipes.