PURPOSE: To provide the liquid crystal display which can be used for both of a reflection type/transmission type in accordance with a condition and is adequate for a portable type computer.

CONSTITUTION: The reflection 1 for the back light of the liquid crystal display with the side light type back light is constituted attachably and detachable and further, the reflection plate 1 is constituted mountable between a liquid crystal cell 100 and a diffusion plate 107. The liquid crystal display is usable for both the transmission type and the reflection type in accordance with the condition by providing the rear surface of the liquid crystal cell 100 with the attachable and detachable reflection plate 1. The operability is thus improved and simultaneously, the electric power consumption is reduced.