Process for producing a norbornene polymer

A process for producing a norbornene polymer consisting essentially of a repeating unit of formula (I):

• ##STR11## wherein R.sup.1 to R.sup.12 are the same or different and are independently a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, an oxygen atom or a nitrogen atom;
• R.sup.5 and R.sup.7 may combine together to form a ring;
• and n is an integer of 0 or more, and having a weight average molecular weight of 1.times.10.sup.5 to 1.times.10.sup.7 as determined by gel permeation chromatography, which process comprises polymerizing a norbornene monomer of the formula (II):
• ##STR12## wherein R.sup.1 to R.sup.12 are the same or different and are independently a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a substituent containing a halogen atom, an oxygen atom or a nitrogen atom;
• R.sup.5 and R.sup.7 may combine together to form a ring;
• and n is an integer of 0 or more, in the presence of a catalyst comprising a transition metal compound component containing a transition metal selected from the group consisting of manganese, nickel and palladium, and an aluminoxane component.