Temperature sensor and temperature measurement system

A temperature sensor configured to measure a temperature of a resin filling a die in a resin molding device, the temperature sensor comprising:

• a metal sheath having a bottomed cylindrical shape;
• a pair of thermocouple element wires accommodated in the metal sheath;
• and
• an insulator provided around the pair of thermocouple element wires in the metal sheath, wherein
• the temperature sensor is a grounded sheath thermocouple including a tip as a temperature measuring contact for the resin,
• the temperature sensor further includes a housing covering a periphery of a tip portion of the metal sheath, and
• a tip as one side surface of the metal sheath has a planar shape, wherein
• the metal sheath comprises:
• a columnar portion that functions as a temperature sensing portion that has a columnar shape and comprises the one side surface;
• and
• a cylindrical portion that is provided upright from the columnar portion and that has a cylindrical shape, wherein
• the columnar portion and the cylindrical portion are integrally formed of a same material, and wherein
• each of the pair of the thermocouple element wires has one end side welded to another side surface of the columnar portion of the metal sheath.