An LED lamp A1 includes at least one elongated LED unit 1 including a plurality of light emitting diodes 13, and bases 2 and 3 configured to be attached to the ends of the LED unit 1 in the longitudinal direction to receive power from outside. The lamp is configured to allow a plurality of LED units 1 to be serially connected. Such configuration contributes to reducing the manufacturing cost and facilitating the management of the products, with respect to a plurality of types of products of different lengths.