A rehabilitation exercise device for upper and lower limbs, the rehabilitation exercise device comprising: a first support supporting a user's hand or foot; a second support supporting a user's forearm or calf; a pair of first hinges rotatably connecting the first support and the second support to each other; a third support supporting a user's upper arm or thigh; a pair of second hinges rotatably connecting the second support and the third support to each other; and a distance adjustment part configured to adjust a distance between the first support and the third support by adjusting length of the second support, wherein the second support comprises: a first fixing plate connected to the pair of first hinges to be rotatably coupled to the first support; a second fixing plate connected to the pair of second hinges to be rotatably coupled to the third support, and configured to be mutually approached or spaced apart with respect to the first fixing plate by the distance adjustment part; a hinge shaft provided between the first fixing plate and the second fixing plate; a first moving plate provided between the first fixing plate and the hinge shaft, and configured to be reciprocally moved therebetween; and a second moving plate provided between the second fixing plate and the hinge shaft, and configured to be reciprocally moved therebetween, wherein the distance adjustment part comprises: a first crank rotatably connected to the first fixing plate and the hinge shaft, and configured to convert a rotary motion of the hinge shaft into a linear motion of the first fixing plate; and a second crank rotatably connected to the second fixing plate and the hinge shaft, and is configured to convert the rotary motion of the hinge shaft into a linear motion of the second fixing plate. a first support supporting a user's hand or foot; a second support supporting a user's forearm or calf; a pair of first hinges rotatably connecting the first support and the second support to each other; a third support supporting a user's upper arm or thigh; a pair of second hinges rotatably connecting the second support and the third support to each other; and a distance adjustment part configured to adjust a distance between the first support and the third support by adjusting length of the second support, wherein the second support comprises: a first fixing plate connected to the pair of first hinges to be rotatably coupled to the first support; a second fixing plate connected to the pair of second hinges to be rotatably coupled to the third support, and configured to be mutually approached or spaced apart with respect to the first fixing plate by the distance adjustment part; a hinge shaft provided between the first fixing plate and the second fixing plate; a first moving plate provided between the first fixing plate and the hinge shaft, and configured to be reciprocally moved therebetween; and a second moving plate provided between the second fixing plate and the hinge shaft, and configured to be reciprocally moved therebetween, wherein the distance adjustment part comprises: a first crank rotatably connected to the first fixing plate and the hinge shaft, and configured to convert a rotary motion of the hinge shaft into a linear motion of the first fixing plate; and a second crank rotatably connected to the second fixing plate and the hinge shaft, and is configured to convert the rotary motion of the hinge shaft into a linear motion of the second fixing plate. a first fixing plate connected to the pair of first hinges to be rotatably coupled to the first support; a second fixing plate connected to the pair of second hinges to be rotatably coupled to the third support, and configured to be mutually approached or spaced apart with respect to the first fixing plate by the distance adjustment part; a hinge shaft provided between the first fixing plate and the second fixing plate; a first moving plate provided between the first fixing plate and the hinge shaft, and configured to be reciprocally moved therebetween; and a second moving plate provided between the second fixing plate and the hinge shaft, and configured to be reciprocally moved therebetween, wherein the distance adjustment part comprises: a first crank rotatably connected to the first fixing plate and the hinge shaft, and configured to convert a rotary motion of the hinge shaft into a linear motion of the first fixing plate; and a second crank rotatably connected to the second fixing plate and the hinge shaft, and is configured to convert the rotary motion of the hinge shaft into a linear motion of the second fixing plate. a first crank rotatably connected to the first fixing plate and the hinge shaft, and configured to convert a rotary motion of the hinge shaft into a linear motion of the first fixing plate; and a second crank rotatably connected to the second fixing plate and the hinge shaft, and is configured to convert the rotary motion of the hinge shaft into a linear motion of the second fixing plate.