An exercise device, including: a frame, including a weighting seat which is movable, two first movable pulley assemblies (12, 12') and two second movable pulley assemblies (13, 13'); a first operation assembly, disposed on the frame, including two first connecting members and a first cable; a second operation assembly, including two second connecting members and two second cables; and a third operation assembly, including two third connecting members and two third cables, each of the two third cables being connected to the frame and curving back around one of the two second movable pulley assemblies (13, 13'), each of the two third cables being connected to an end of one of the two third connecting members; characterized in that the first cable curving back around one of the two first movable pulley assemblies (12, 12'), the weighting seat and the other of the two first movable pulley assemblies (12, 12') sequentially, and the two first connecting members are fixedly connected to opposing ends of the first cable respectively; each of the two second cables being connected to the frame and curving back around one of the two first movable pulley assemblies (12, 12') and one of the two second movable pulley assemblies (13, 13'), and each of the two second connecting members is fixedly connected to an end of one of the two second cables; each of the two first connecting members is stoppable by the frame and movable away from the frame; and each of the two second cables has an end fixed to the frame, and each of the two second connecting members is stoppable by the frame and movable away from the frame. a frame, including a weighting seat which is movable, two first movable pulley assemblies (12, 12') and two second movable pulley assemblies (13, 13'); a first operation assembly, disposed on the frame, including two first connecting members and a first cable; a second operation assembly, including two second connecting members and two second cables; and a third operation assembly, including two third connecting members and two third cables, each of the two third cables being connected to the frame and curving back around one of the two second movable pulley assemblies (13, 13'), each of the two third cables being connected to an end of one of the two third connecting members; characterized in that the first cable curving back around one of the two first movable pulley assemblies (12, 12'), the weighting seat and the other of the two first movable pulley assemblies (12, 12') sequentially, and the two first connecting members are fixedly connected to opposing ends of the first cable respectively; each of the two second cables being connected to the frame and curving back around one of the two first movable pulley assemblies (12, 12') and one of the two second movable pulley assemblies (13, 13'), and each of the two second connecting members is fixedly connected to an end of one of the two second cables; each of the two first connecting members is stoppable by the frame and movable away from the frame; and a third operation assembly, including two third connecting members and two third cables, each of the two third cables being connected to the frame and curving back around one of the two second movable pulley assemblies (13, 13'), each of the two third cables being connected to an end of one of the two third connecting members; characterized in that the first cable curving back around one of the two first movable pulley assemblies (12, 12'), the weighting seat and the other of the two first movable pulley assemblies (12, 12') sequentially, and the two first connecting members are fixedly connected to opposing ends of the first cable respectively; each of the two second cables being connected to the frame and curving back around one of the two first movable pulley assemblies (12, 12') and one of the two second movable pulley assemblies (13, 13'), and each of the two second connecting members is fixedly connected to an end of one of the two second cables; each of the two first connecting members is stoppable by the frame and movable away from the frame; and each of the two second cables has an end fixed to the frame, and each of the two second connecting members is stoppable by the frame and movable away from the frame.