A vibrating fat eliminating device (100, 100A, 100B, 100C), comprising: a vibrating main body (200, 200A, 200B, 200C) comprising a fixing notch (210, 210A, 210C) and an upper surface (220, 220A, 220C), wherein the fixing notch (210, 210A, 210C) is disposed on the upper surface (220, 220A, 220C); a chair body (300, 300A, 300B, 300C) detachably disposed on the vibrating main body (200, 200A, 200B, 200C) and comprising a supporting frame (310, 310B) and a cushion (320, 320B), wherein the supporting frame (310, 310B) is disposed on the upper surface (220, 220A, 220C), the cushion (320, 320B) is disposed on the supporting frame (310, 310B), and the supporting frame (310, 310B) comprises a connecting portion (330, 330A); characterized in that the connecting portion (330, 330A) has a through hole (331, 331A); and the vibrating fat eliminating device (100, 100A, 100B, 100C) further comprises a positioning unit (400, 400A, 400B, 400C) passing through the through hole (331, 331A) and connected to the fixing notch (210, 210A, 210C) correspondingly, so that the chair body (300, 300A, 300B, 300C) is detachably disposed on the upper surface (220, 220A, 220C) via the positioning unit (400, 400A, 400B, 400C); wherein the fixing notch (210, 210A, 210C) comprises an internal connecting portion, the positioning unit (400, 400A, 400B, 400C) comprises a fixing rod, an elastic member, at least two washers and a knob, wherein the fixing rod comprises a connecting end for connecting with the internal connecting portion, the knob being disposed on one side of the fixing rod which is different from the connecting end, and the fixing rod being passed through in order from the elastic member, one of the washers, the through hole (331, 331A) and the other one of the washers, and then is connected to the fixing notch (210, 210A, 210C). a vibrating main body (200, 200A, 200B, 200C) comprising a fixing notch (210, 210A, 210C) and an upper surface (220, 220A, 220C), wherein the fixing notch (210, 210A, 210C) is disposed on the upper surface (220, 220A, 220C); a chair body (300, 300A, 300B, 300C) detachably disposed on the vibrating main body (200, 200A, 200B, 200C) and comprising a supporting frame (310, 310B) and a cushion (320, 320B), wherein the supporting frame (310, 310B) is disposed on the upper surface (220, 220A, 220C), the cushion (320, 320B) is disposed on the supporting frame (310, 310B), and the supporting frame (310, 310B) comprises a connecting portion (330, 330A); characterized in that the connecting portion (330, 330A) has a through hole (331, 331A); and the vibrating fat eliminating device (100, 100A, 100B, 100C) further comprises a positioning unit (400, 400A, 400B, 400C) passing through the through hole (331, 331A) and connected to the fixing notch (210, 210A, 210C) correspondingly, so that the chair body (300, 300A, 300B, 300C) is detachably disposed on the upper surface (220, 220A, 220C) via the positioning unit (400, 400A, 400B, 400C); wherein the fixing notch (210, 210A, 210C) comprises an internal connecting portion, the positioning unit (400, 400A, 400B, 400C) comprises a fixing rod, an elastic member, at least two washers and a knob, wherein the fixing rod comprises a connecting end for connecting with the internal connecting portion, the knob being disposed on one side of the fixing rod which is different from the connecting end, and the fixing rod being passed through in order from the elastic member, one of the washers, the through hole (331, 331A) and the other one of the washers, and then is connected to the fixing notch (210, 210A, 210C).