The present invention relates to a device for treating obesity using low-cost cooling, the device being capable of treating obesity by spreading an anti-freezing agent to a part to be treated without use of an absorption pad or a coupling device, but by surrounding the part with a film to protect the skin, and cooling only the fat portion. The device according to the present invention comprises: 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. The device may further comprise a film for sealing an anti-freezing agent 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. According to the present invention, metallic cooling plates are in-molded in a suction cup made of silicone and, instead of making direct contact with the part to be treated, makes contact via a thin silicone layer such that fat can be destroyed efficiently using a small amount of anti-freezing agent while protecting the skin. Further, any gap through which air may flow in is removed, thereby improving suction force, and use of a liner or an absorption pad and a coupling device is not required, thus reducing cost.