An optical sheet 50 includes: a particle layer 55 that has a first side and a second side facing each other, the particle layer 55 including a holding section 56 that includes a cavity 56a and a particle 60 that is contained in the cavity 56a and includes a first polymer section 61 and a second polymer section 62; a first base material 51 provided on the first side of the particle layer 55; a second base material 52 provided on a second side of the particle layer 55; and diffusing sections 53 and 58 provided on the second side of the particle layer 55.