To solve a problem wherein a thin-walled flexible part is easily broken due to the concentration of stress during use when a mounting shaft body is inserted into an insertion hole on a damper main body side and they are integral ly molded in a viscous fluid sealing damper preventing vibration of and supporting an on-vehicle disc player.

In this viscous fluid sealing damper 16, the shaft body 20 is constituted by providing an insertion part 46 into the insertion hole 44 in a stirring part 28 and a large-diameter part 48 having a close adhesion face 56 to an outer face of a flexible part 30 using a hard resin material. The stirring part 28 and the flexible part 30 are molded integrally with the shaft body 20 while they are mutually joined using a soft resin material. A thick-walled part 80 is formed in a part on more outer peripheral side than the large-diameter part 48 in the flexible part 30, and an inner peripheral face of the thick-walled part 80 is joined and integrated with an outer peripheral face of the large- diameter part 48.