To highly uniformize the quantity of reactants to be blown off in the width direction of the material to be vapor-deposited.

A vacuum vapor deposition device 3 is the one in which primary to fourth oxygen blow-off pipes 6a, 6b, 6c and 6d are provided dividedly in the width direction of a synthetic resin film, and through these primary to fourth oxygen flow-off pipes 6a, 6b, 6c and 6d, oxygen is blown off into the vapor of aluminum. In this way, the quantity of oxygen to be blonw off from each oxygen blow-off hole of each oxygen blow-off pipe is made uniform, and the dispersion of the reaction between aluminum and oxygen in the width direction of the synthetic resin film can be solved. Moreover, the flow rates in respective primary to fourth oxygen feed pipes 10, 11, 12 and 13 are measured by primary to fourth manometers 19, 20, 21 and 22, and based on the measured results, so that the quantity to be blown off from the primary to fourth oxygen blow-off pipes 6a, 6b, 6c and 6d is made uniform and primary to fourth flow regulating valves 15, 16, 17 and 18 are controlled. In this way, the quantity of oxygen to be blown off can moreover be uniformized.