An attachment structure for a temperature sensor that is attached to a flexible thin plate-shaped cable and detects the temperature of a unit cell of a battery pack having a plurality of unit cells connected with each other includes: the flexible thin plate-shaped cable; a chip-shaped temperature measuring element that is incorporated on a conductor exposed portion of the flexible thin plate-shaped cable and detects the temperature of the unit cell; and a metal leaf spring that is placed around the conductor exposed portion of the flexible thin plate-shaped cable and has a plurality of legs surrounding the temperature measuring element, and an elastic piece configured to energize the plurality of legs toward the unit cell. The temperature measuring element is sheathed with a moisture-proof material between the plurality of legs of the metal leaf spring.