PURPOSE: To prevent the overflow of a viscous fluid and perform the bonding of a lid body perfectly by bonding the lid body to a cylindrical container body with its closed bottom, placing the bottom part upward and injecting the viscous fluid from the inlet of the bottom part.

CONSTITUTION: A thermoplastic resin made container body 32 is molded, and a rubber lid body 34 is vulcanization-molded to be bonded to the container body 32. The bottom part 30 of the container body 32 is placed upward, and the tip of an injector 47 is inserted from a small hole 36 so as to inject the fixed quantity of a viscous fluid 46. The peripheral part of the small hole 36 is then heated and deposited to fill up the small hole 36. A fluid sealed damper can be thus manufactured in a short time, and the viscous fluid is prevented from overflowing as well as the bonding of the lid body is prevented from being impeded by the viscous fluid adhered to a mating face 33.