To provide a method producing a polyolefin, capable of producing a polymer having high stereoselectivity and good particle properties in high polymerization activity and stably preventing a catalyst feed pipe to a polymerization zone from clogging for a long period.
A preliminary polymerization catalyst obtained by preliminarily polymerizing an α-olefin in the presence of [A] a solid titanium compound consisting essentially of magnesium, titanium, a halogen and an electron donor with [B] an organoaluminum compound is brought into contact with a halogenating agent such as iodine, ethylaluminum dichloride, ethlaluminum sesquichloride or ethyl iodine and continuously fed to a polymerization zone of the α-olefin independently from the organoaluminum compound to produce the objective polyolefin.
TSUBOI KATSUFUMI
ITO JUNICHI
