Process for producing polyethylene

A process or apparatus for producing polyethylene with improved film thinning and handleability involves polymerizing high-pressure ethylene using an autoclave-type reactor in the presence of a polymerization initiator. The reaction zone of the reactor has at least two different temperature sections; the polymerization initiator and the ethylene are supplied to the upstream temperature section in the reaction zone and the ethylene is polymerized to generate polyethylene; unreacted ethylene and the polyethylene generated at the upstream temperature section in the reactor flow into the downstream temperature section in communication with the upstream temperature section, so that additional polyethylene is generated at the downstream temperature section. A difference (ΔT [° C.]) between a temperature (T1 [° C.]) of the temperature section positioned upstream and a temperature (T2 [° C.]) of the temperature section positioned downstream in the reaction zone that receives the polymerization initiator and is in the autoclave-type reactor is 2.1° C. to 8.4° C.