PURPOSE: To measure the temperature of a liquid resin stably and accurately without requiring work of removing an attached layer with the removal of a thermocouple.

CONSTITUTION: A thermocouple 3 is mounted on a wall surface of a discharge chute 2 for discharging a liquid resin 1 with the tip thereof projecting into the discharge chute 2. A cylindrical spool 4 is mounted on the outer circumference of the thermocouple 3 free to slide along the length of the thermocouple 3 so that the tip thereof is positioned near a wall surface of the discharge chute 2. A spool drive mechanism 5 is provided to slide the spool 4 to a position at which the tip thereof sticks out ahead of the tip of the thermocouple 3. A deposited layer 12 of the resin liquids 1 on the tip of the thermocouple 3 is pushed off with the tip of the spool 4.