A fitness exercise apparatus including: a main frame including a base seat and a support unit that is connected to said base seat; a seat unit mounted detachably on said base seat; a transmission unit including a first fixed pulley set that is mounted on said support unit, two second fixed pulley sets that are mounted on said support unit, two third fixed pulley sets that are mounted on said base seat, a first movable pulley that is disposed above said base seat and that is proximate to said support unit a movable pulley set that is disposed at a side of said first movable pulley, two second movable pulleys that are disposed respectively at opposite sides of said first movable pulley, a first cable that wraps around said first fixed pulley set, said first movable pulley and said movable pulley set, two second cables, each wrapping around a respective one of said second movable pulleys and a respective one of said second fixed pulley sets, and a third cable that wraps around said third fixed pulley set and said movable pulley set, and that is connected to said second movable pulleys; and an operating unit including at least one operating member (51, 52, 53) that is connected to one of said first and second cables (47, 48); characterized in that said fitness exercise apparatus further includes: a resistance unit including a weight subunit that is mounted on said main frame, and an elastic subunit that is connected between said weight subunit and said main frame; wherein pulling of said first cable drives said first movable pulley to move upwardly, thereby resulting in movement of said weight subunit against an elastic force of said elastic subunit; and wherein pulling of said second cables drives said second movable pulleys to move upwardly, thereby pulling said first cable via said third cable and said movable pulley set, and eventually resulting in movement of said weight subunit against an elastic force of said elastic subunit a main frame including a base seat and a support unit that is connected to said base seat; a seat unit mounted detachably on said base seat; a transmission unit including a first fixed pulley set that is mounted on said support unit, two second fixed pulley sets that are mounted on said support unit, two third fixed pulley sets that are mounted on said base seat, a first movable pulley that is disposed above said base seat and that is proximate to said support unit a movable pulley set that is disposed at a side of said first movable pulley, two second movable pulleys that are disposed respectively at opposite sides of said first movable pulley, a first cable that wraps around said first fixed pulley set, said first movable pulley and said movable pulley set, two second cables, each wrapping around a respective one of said second movable pulleys and a respective one of said second fixed pulley sets, and a third cable that wraps around said third fixed pulley set and said movable pulley set, and that is connected to said second movable pulleys; and a first fixed pulley set that is mounted on said support unit, two second fixed pulley sets that are mounted on said support unit, two third fixed pulley sets that are mounted on said base seat, a first movable pulley that is disposed above said base seat and that is proximate to said support unit a movable pulley set that is disposed at a side of said first movable pulley, two second movable pulleys that are disposed respectively at opposite sides of said first movable pulley, a first cable that wraps around said first fixed pulley set, said first movable pulley and said movable pulley set, two second cables, each wrapping around a respective one of said second movable pulleys and a respective one of said second fixed pulley sets, and a third cable that wraps around said third fixed pulley set and said movable pulley set, and that is connected to said second movable pulleys; and an operating unit including at least one operating member (51, 52, 53) that is connected to one of said first and second cables (47, 48); a resistance unit including a weight subunit that is mounted on said main frame, and an elastic subunit that is connected between said weight subunit and said main frame; wherein pulling of said first cable drives said first movable pulley to move upwardly, thereby resulting in movement of said weight subunit against an elastic force of said elastic subunit; and wherein pulling of said second cables drives said second movable pulleys to move upwardly, thereby pulling said first cable via said third cable and said movable pulley set, and eventually resulting in movement of said weight subunit against an elastic force of said elastic subunit