The present application discloses a catalyst for olefin polymerization, comprising a product of the following components: (A) solid titanium-containing catalyst component comprising magnesium, titanium and halogen as essential components; (B) organo-aluminum compound catalyst component, and (C) silicon ether compound catalyst component, the silicon ether compound being represented by a general formula (I): ##STR00001## wherein R.sub.1-R.sub.12 and A are as defined in the description.