The invention provides an automatic retractable grab back structure, which comprises a body, the body is provided with a chute, the chute is provided with a connecting rod, one end of the connecting rod is connected with a grab back piece, the other end of the connecting rod is connected with the transmission unit, the driving unit is used to control the transmission unit to drive the connecting rod to move in the chute, so as to extend or shorten the exposure of the connecting rod The length of the chute can be controlled according to the itching position of the user's back.本創作係提供一種自動伸縮之抓背構造，含有一本體，該本體開設有一滑槽，該滑槽上設有一連接桿，該連接桿之一端連接有一抓背件，連接桿之另一端係連接該傳動單元，利用驅動單元控制傳動單元以帶動該連接桿於該滑槽內做移動，以伸長或縮短該連接桿露出於該滑槽之長度；本創作可以隨著使用者之背部搔癢位置，控制該抓背件之長度。
