A new gas-flow type reactor for plasma polymerization was developed to synthesize functional polymers, which enhances reaction of radicals activated in the discharge. Styrene was used for the plasma polymerization and molecular strucure and molecular weight distribution of the plasma -polymerized styrene were studies. The ploymer was evaluated to be an efficient electron beam resist. The sensitivity of the plasma-polymerized styrene film formed by this new reactor was better than that of the reported values of conventional polystyrene, Fine resist patterns could be successfully developed by a wet process.