A thermistor comprises a main body, two electric plugs, a metallic fixing piece, and a cover. The electric plugs are located on one end of the main body, and the metallic fixing piece is located on the side of the main body. The metallic fixing piece has a connecting portion up against one side of the main body, and a soldering portion located on the other end of the main body, opposite to the electric plugs and protruding from the main body. The cover is over the main body and the connecting portion of the metallic fixing piece, thereby securing the metallic fixing piece to the main body. The soldering portion of the metallic fixing piece can be soldered directly onto the printed circuit board, thereby anchoring the thermistor to the printed circuit board more securely.