Provided is a lightweight anvil roller and an ultrasonic welding device provided therewith. The anvil roller (10) has: a supported section (19) that is rotatably supported by a holding mechanism (11) via a rotary shaft (12a) in such a manner that the anvil roller (10) can come into rolling contact with a sheet (W)； an outer peripheral section (18) having a welding surface over which the sheet (W) is welded between the outer peripheral section (18) and an ultrasonic horn (6) during rolling contact with the sheet (W)； a thin section (21) that is formed between the supported section (19) and the outer peripheral section (18) in such a manner that the thickness of the thin section (21) is smaller than the thickness of the outer peripheral section (18) in the axial direction of the rotary shaft (12a)； and a vibrationproof member (22) provided on the thin section (21).
