A temperature sensor including: a temperature sensing element (102) having a temperature sensing unit (103) and a pair of device electrode wires (104); a sheath member (106) having a sheath wire (108) connected at a junction (110) to at least one of the device electrode wires and a sheath outer pipe (107) retaining the sheath wire in an insulating material (114); an inner tube (112) which has a bottomed cylindrical shape; and a cylindrical outer tube (120) having an open end, covering the inner tube such that the open end is located at a front end side of the junction and in a region to the rear end side of or aligned with the front end of the inner tube, and being spaced from the inner tube at the front end side of the junction.