A strengthening and rehabilitation exercise apparatus comprising: an exercise frame which is mounted at a stationary frame of the exercise apparatus such that a human body is fixedly placeable on the exercise frame in the prone position; the exercise frame comprising: an upper frame, which is fixed to the stationary frame and configured to support an upper portion of the human body; a lower frame coupled to the upper frame; and a rotary shaft located midway between the upper frame and the lower frame and mounted at one side of the stationary frame such that the rotary shaft interlocks with the hip joint axis of the human body, characterized in that the lower frame comprises: a four-axis link comprising: an inguinal region exercise lever interlocking with the rotary shaft; a calf rest rotatably connected to the inguinal region exercise lever, wherein the calf rest can be adjusted in length by a motor in accordance to a length of each of the inguinal regions of the human body; and a rear lever, wherein a lower end of the rear lever is rotatably connected to the calf rest and an upper end of the rear lever is rotatably coupled to the stationary frame such that the four-axis link is rotatable in parallel and the legs of the human body, as being supported by the four-axis link, are movable in a seesaw fashion; wherein the exercise apparatus further comprises: an exercise resistance controller which is connected to the rotary shaft, wherein the exercise resistance controller is provided with a lever that performs symmetrical rotation while interlocking with the exercise frame, and the lever is provided with a weight mechanism to minimize initial exercise load, wherein the exercise resistance controller comprises: a brake wheel mounted at the rotary shaft of the weight mechanism; an additional electromagnetic brake; and an amplifier interlocking with the brake wheel. an upper frame, which is fixed to the stationary frame and configured to support an upper portion of the human body; a lower frame coupled to the upper frame; and a rotary shaft located midway between the upper frame and the lower frame and mounted at one side of the stationary frame such that the rotary shaft interlocks with the hip joint axis of the human body, characterized in that the lower frame comprises: a four-axis link comprising: an inguinal region exercise lever interlocking with the rotary shaft; a calf rest rotatably connected to the inguinal region exercise lever, wherein the calf rest can be adjusted in length by a motor in accordance to a length of each of the inguinal regions of the human body; and a rear lever, wherein a lower end of the rear lever is rotatably connected to the calf rest and an upper end of the rear lever is rotatably coupled to the stationary frame such that the four-axis link is rotatable in parallel and the legs of the human body, as being supported by the four-axis link, are movable in a seesaw fashion; wherein the exercise apparatus further comprises: an exercise resistance controller which is connected to the rotary shaft, wherein the exercise resistance controller is provided with a lever that performs symmetrical rotation while interlocking with the exercise frame, and the lever is provided with a weight mechanism to minimize initial exercise load, wherein the exercise resistance controller comprises: a brake wheel mounted at the rotary shaft of the weight mechanism; an additional electromagnetic brake; and an amplifier interlocking with the brake wheel. a brake wheel mounted at the rotary shaft of the weight mechanism; an additional electromagnetic brake; and an amplifier interlocking with the brake wheel.