A lighting unit, e.g. an LED bulb or a straight LED luminaire, which illuminates a wide range and is configured with low cost. In a light-emitting diode lamp, a board assembly is disposed in a lamp main body, and light-emitting diodes are attached to the board assembly. The board assembly comprises a plurality of flexible printed circuit boards. Each flexible printed circuit board includes a base in the form of a flat plate, respective connections to a power supply portion of the light-emitting diode lamp are provided at two ends of the base, and the base is bent at a plurality of points of a middle portion to form a top surface portion and side surface portions. The flexible printed circuit boards are three-dimensionally assembled such that the top surface portions cross each other and such that one of the top surface portions lies on top of another.