The present invention provides a process for producing an alkoxy-titanium complex of formula (2) by reacting a titanium halide complex of formula (1) with an alkaline earth metal alkoxide: ##STR00001## wherein A denotes a Group 14 element in a periodic table; R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are the same or different and denote a hydrogen atom, halogen, a C.sub.1-20 alkyl group which may be substituted by halogen, a C.sub.6-20 aryl group which may be substituted by halogen, or the like; R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are the same or different and independently denote a hydrogen atom, halogen, a C.sub.1-20 alkyl group which may be substituted by halogen, or the like; and X.sup.1 and X.sup.2 independently denote any halogen atom: ##STR00002## wherein R.sup.11 and R.sup.12 are the same or different and independently denote a C.sub.1-20 alkyl group which may be substituted by halogen, or the like.