A light guide optical device includes an optical path combiner including: a first deflector to deflect first light incident from a first direction to an emission direction; a second deflector to deflect second light incident from a second direction different from the first direction, to the emission direction; and a transmission portion between the first deflector and the second deflector, the transmission portion to transmit third light incident from a third direction different from each of the first direction and the second direction, to the emission direction. The optical path combining unit combines the first light, the second light, and the third light, and emits the combined light to the mission direction.