To provide a thermoregulator which enables for easy readjustment of a scale, without the need for using special tools on site.

To allow for easy readjustment of a scale on site, the thermoregulator is provided with a setting groove 211 for checking a position of an indicator needle 205, an attachment bracket 210 with a fixed nut 209, a setting screw 208 which moves in the axial direction to the nut 209 depending on the amount of rotating motion, a lock plate 206 for retaining one end of the setting screw 208 at the rear side, a setting groove 222 mounted on the peripheral area of the lock plate 206, a protrusion 207 which is located at the front side of the lock plate 206 and has screw heads in the inner and outer peripheral areas, a indicator 204 which is fixed to the protrusion 207 by an indicator retention nut 203, the indicator needle 205 and an adjustment marking 230 to be indicated on the indicator 204, and a detachable setting knob 202 which is screwed to the protrusion 207.