A device for treating obesity using cooling, comprising: a controller body for setting a cooling temperature and operating time, supplying cooling water for cooling a thermoelectric element, and providing suction force through a vacuum pump; a handpiece body for displaying operating conditions and providing suction force through a suction hole; a cable for connecting the controller body and the handpiece body; a suction cup mounted on the handpiece body to form a suction space; and cooling devices positioned on opposite sides of the suction cup to cool a part to be treated, which has been sucked into the suction space; and a film for sealing an anti-freezing agent configured to be applied to the part to be treated to facilitate penetration of the anti-freezing agent into the part to be treated and to prevent the suction cup from being smeared with the anti-freezing agent, a cup body made of a silicone material and configured such that a bottom surface of the cup body is fitted into the handpiece body and a first surface of the cup body making contact with the part to be treated is open to form the suction space for sucking the part to be treated inside the cup body; characterised in that the suction cup body further comprises: cooling plates in-molded on opposite sides of the cup body in the cup body, wherein the cooling plates make contact with the part to be treated via a silicone layer instead of making direct contact with the part to be treated so that the device efficiently destroys fat using a small amount of anti-freezing agent while protecting a skin, and removes any gap through which air flows in, thereby increasing suction force. a controller body for setting a cooling temperature and operating time, supplying cooling water for cooling a thermoelectric element, and providing suction force through a vacuum pump; a handpiece body for displaying operating conditions and providing suction force through a suction hole; a cable for connecting the controller body and the handpiece body; a suction cup mounted on the handpiece body to form a suction space; and cooling devices positioned on opposite sides of the suction cup to cool a part to be treated, which has been sucked into the suction space; and a film for sealing an anti-freezing agent configured to be applied to the part to be treated to facilitate penetration of the anti-freezing agent into the part to be treated and to prevent the suction cup from being smeared with the anti-freezing agent, a cup body made of a silicone material and configured such that a bottom surface of the cup body is fitted into the handpiece body and a first surface of the cup body making contact with the part to be treated is open to form the suction space for sucking the part to be treated inside the cup body; characterised in that the suction cup body further comprises: cooling plates in-molded on opposite sides of the cup body in the cup body, wherein the cooling plates make contact with the part to be treated via a silicone layer instead of making direct contact with the part to be treated so that the device efficiently destroys fat using a small amount of anti-freezing agent while protecting a skin, and removes any gap through which air flows in, thereby increasing suction force. cooling plates in-molded on opposite sides of the cup body in the cup body, wherein the cooling plates make contact with the part to be treated via a silicone layer instead of making direct contact with the part to be treated so that the device efficiently destroys fat using a small amount of anti-freezing agent while protecting a skin, and removes any gap through which air flows in, thereby increasing suction force.