Light guide device and virtual-image display device

A light guide device comprising:

• a light guide body including a pair of opposed surfaces corresponding to an observer side and an external environment side;
• an incident section provided on one end side of the light guide body;
• and
• an emitting section provided on the other end side of the light guide body, wherein
• the emitting section includes a reflection unit formed by arraying a plurality of mirrors that respectively emit video lights received from the incident section to the observer side, and
• the plurality of mirrors are reflection elements having reflectance of P polarized light lower than reflectance of S polarized light.