DISPLAY DEVICE

PROBLEM TO BE SOLVED: To improve the assembly characteristic of a display device capable of effectively curving and guiding the exit light from a light emitting element and recognizing this light, to facilitate the mounting of the device to a circuit board and to make positioning accuracy exact. SOLUTION: This display device consists of a transparent light transmission body 12 which has a photodetecting surface 15 for making the exit light of the light emitting element on the circuit board incident, a slope 16 for reflecting the incident light in a front surface direction, a light guiding part 27 for guiding the reflected light to the front surface side and a flat detaining piece part 18 projectingly formed on the rear surface side and a light transmission body holding member 14 which has a front surface side opening 31 to be made peepable to the front surface by fitting this light guiding part into the inside, a rear surface side opening 32 for engaging the detaining piece part 18 with the rear surface side by fitting this part therein and an engaging part 29 for detaining the circuit board by engaging with the circuit board.