A lighting unit to be used for illumination includes an LED unit having a
semiconductor light emitting unit, a radiating board for directly fixing
the semiconductor light emitting unit to an upper surface, and a contact
formed on the radiating board and serving to input a power to cause the
semiconductor light emitting unit to emit a light, an attachment having a
power supply portion for surrounding and holding the LED unit and
supplying a power to cause the semiconductor light emitting unit to emit
a light from an external power plug to the contact in a state in which at
least a part of lower and side surfaces of the radiating board and an
upper part of the semiconductor light emitting unit are open.