A photocatalyst cellular component (100) and a photocatalytic purification apparatus (10), increasing to the greatest extent a contact area between polluted air and a photocatalyst, ensuring to the greatest extent that a sufficient amount of ultraviolet rays is shone onto the surface of the photocatalyst, and, at the same time, allowing the flow resistance applied to air flowing in a flow channel to also satisfy the field of ventilation systems having increased requirements on flow resistance. The photocatalyst cellular component (100) is constituted by one or more photocatalyst cellular filter cores (110) and a photocatalyst cellular component housing (120). The photocatalyst cellular component filter cores (110) employ a cellular arrangement. The photocatalyst cellular filter cores (110) are constituted by three or more filter core basic units (111´) and a light guide component (115´) that is Y-shaped when viewed from an end. In the three filter core basic units (111´) adjacently paired with each other, a first filter core basic unit (111´a) and a second filter core basic unit (111´b) are provided with a shared first light guide plate (111´ab1), the first filter core basic unit (111´a) and a third filter core basic unit (111´c) are provided with a shared second light guide plate (111´ac1), the second filter core basic unit (111´b) and the third filter core basic unit (111´c) are provided with a shared third light guide plate (111´bc1), and the first to third light guide plates (111´ab1, 111´ac1, and 111´bc1) constitute the light guide component (115´).Linvention concerne un élément alvéolaire photocatalyseur (100) et un appareil de purification photocatalytique (10), augmentant autant que faire se peut une zone de contact entre un air pollué et un photocatalyseur, assurant dans toute la mesure du possible quune quantité suffisante de rayonnements ultraviolets soit émise sur la surface du photocatalyseur, et, parallèlement, permettant à la résistance à lécoulement
