A thermoregulator, comprising: a shell having an inner cavity therein; a pushrod disposed in the shell; a heat-sensitive element disposed in the shell and adapted to push the pushrod to move by expanding with heat, inner and outer valve bodies disposed in the shell; a sealing member mounted on the outer valve body and having an inner ring surface and an outer ring surface, and an elastic member disposed between the shell and the inner valve body, wherein the sealing member and the outer valve body encircle the inner valve body, wherein the sealing member and the inner valve body divide the inner cavity of the shell into a first cavity and a second cavity, and the elastic member normally pushes the inner valve body in a first direction from the first cavity toward the second cavity, wherein the inner ring surface of the sealing member is adapted to contact with the inner valve body, and the outer ring surface of the sealing member is adapted to contact with the shell such that the liquid is prevented from flowing between the first cavity and the second cavity, wherein when a temperature of the liquid in the second cavity is higher than a first predetermined temperature and lower than a second predetermined temperature, the heat-sensitive element is expanded to push the pushrod and thus the inner valve body to move in a second direction opposed to the first direction such that the inner ring surface is separated from the inner valve body and the outer ring surface of the sealing member is contacted with the shell; wherein when the temperature of the liquid in the second cavity is equal to or higher than the second predetermined temperature, the inner valve body is contacted with the outer valve body to move the outer valve body in the second direction such that the outer ring surface is separated from the shell; wherein the outer valve body comprises an upper ring element and a lower ring element, wherein the sealing member is sandwiched in between the upper ring element and the lower ring element, wherein the sealing member, the upper ring element and the lower ring element are fixed to one another, and wherein the inner valve body comprises a substrate plate, a first guide part formed on a lower side of the substrate plate, and a second guide part formed on an upper side of the substrate plate, characterized in that the lower ring element has a first center hole, and the first guide part is disposed in the first center hole via a clearance fit, and the shell has a second guide hole, and the second guide part is disposed in the second guide hole via a clearance fit; and the first guide part comprises a plurality of guide plates arranged along the peripheral direction of a center cylindrical part so that gaps between adjacent guide plates are provided that form a plurality of interspaces for liquid flowing. a shell having an inner cavity therein; a pushrod disposed in the shell; a heat-sensitive element disposed in the shell and adapted to push the pushrod to move by expanding with heat, inner and outer valve bodies disposed in the shell; a sealing member mounted on the outer valve body and having an inner ring surface and an outer ring surface, and an elastic member disposed between the shell and the inner valve body, wherein the sealing member and the outer valve body encircle the inner valve body, wherein the sealing member and the inner valve body divide the inner cavity of the shell into a first cavity and a second cavity, and the elastic member normally pushes the inner valve body in a first direction from the first cavity toward the second cavity, wherein the inner ring surface of the sealing member is adapted to contact with the inner valve body, and the outer ring surface of the sealing member is adapted to contact with the shell such that the liquid is prevented from flowing between the first cavity and the second cavity, wherein when a temperature of the liquid in the second cavity is higher than a first predetermined temperature and lower than a second predetermined temperature, the heat-sensitive element is expanded to push the pushrod and thus the inner valve body to move in a second direction opposed to the first direction such that the inner ring surface is separated from the inner valve body and the outer ring surface of the sealing member is contacted with the shell; wherein when the temperature of the liquid in the second cavity is equal to or higher than the second predetermined temperature, the inner valve body is contacted with the outer valve body to move the outer valve body in the second direction such that the outer ring surface is separated from the shell; wherein the outer valve body comprises an upper ring element and a lower ring element, wherein the sealing member is sandwiched in between the upper ring element and the lower ring element, wherein the sealing member, the upper ring element and the lower ring element are fixed to one another, and wherein the inner valve body comprises a substrate plate, a first guide part formed on a lower side of the substrate plate, and a second guide part formed on an upper side of the substrate plate, characterized in that the lower ring element has a first center hole, and the first guide part is disposed in the first center hole via a clearance fit, and the shell has a second guide hole, and the second guide part is disposed in the second guide hole via a clearance fit; and the first guide part comprises a plurality of guide plates arranged along the peripheral direction of a center cylindrical part so that gaps between adjacent guide plates are provided that form a plurality of interspaces for liquid flowing.