Fixing device capable of grounding tubular member

A fixing device for thermally fixing a developing agent image to a sheet comprising:na flexible tubular member having an inner peripheral surface defining an internal space;a heater disposed at the internal space;a nip member disposed at the internal space and configured to be in sliding contact with the inner peripheral surface of the flexible tubular member, the nip member having an electrically conductive surface;a stay disposed at the internal space to support the nip member, the stay being electrically conductive and electrically connected to the electrically conductive surface;a backup member configured to nip the flexible tubular member in cooperation with the nip member, the backup member including a shaft having an electric conductivity;a supporting member configured to support the nip member and the stay, the supporting member being movable relative to the backup member;a first grounding member disposed to be in contact with the stay for grounding the stay, the first grounding member being supported by the supporting member such that the first grounding member is integrally movable with the supporting member; anda second grounding member connected to the shaft for grounding the shaft, the first grounding member being movable relative to the second grounding member in conjunction with movement of the supporting member relative to the backup member, the second grounding member being electrically connectable to the first grounding member via the shaft.