PURPOSE: To provide a process for producing an odorless molded article of a norbornene polymer by preventing the impregnation of monomer into a filler.

CONSTITUTION: A norbornene polymer is produced by the bulk-polymerization of a norbornene-type monomer in the presence of porous fine powder using a metathesis catalyst system. The above process is carried out by using a master-batch composed of a high-boiling inert oil and porous fine powder coated with a coating film of a polymer free from activity to inhibit metathesis polymerization and applied to the powder in a state dissolved in a volatile solvent.