A temperature sensor having a structure in which electrode wires are butted against signal wires with their weld portions and a method for manufacturing the temperature sensor. In a temperature sensor (1), outer circumferential portions (57a) and (57b) of each of weld portions (55) between electrode wires (25) and sheath core wires (3) are located outward of a first straight line D1 and a second straight line D2, respectively. A forward end-side length L1 is set to be longer than a rear end-side length L2. In addition, the sheath core wires (3) are larger in diameter than the electrode wires (25).