A light guide plate includes: an annular part formed in an annular shape along an element array of multiple light emitting elements; and an annular inner part formed on an annular inside of the annular part continuously with the annular part. The annular part includes: an element array-facing part which is a part facing the element array and which has an incident surface to allow light emitted from the light emitting elements to enter; and a first reflecting part which is a part located closer to the annular inner part than the element array-facing part, and which has a reflecting surface for reflecting the light entering from the incident surface toward the annular inner part. The first reflecting part includes a first light scattering region having a light scattering treatment applied thereto.