To solve the problem that a lighting device is compelled to change its installation position from an optimal position and cannot provides a sufficient illumination in a conventional refrigerated open showcase having a cold air outlet at an upper end of a showcase, which is the optimal installation position for the lighting device for illuminating the inside of a chamber.

This lighting device is equipped with an LED lamp to a circuit board with an outlet so that the cold air outlet and the lighting device are installed at the same position. This constitution can satisfy the lighting effect on the inside of the chamber, prevent dew condensation, which is formed on the cold air outlet due to the contact with outside air, due to the same position of both by the heat generated by the LED lamp and contribute to the energy saving effect such as stopping the use of heater for dew condensation preventing during the lighting.