To inhibit the attractiveness of a ceiling material from deteriorating. According to a passenger compartment material structure (10), on a ceiling material (12), there is disposed a water guide portion (34) that guides water (W) flowing on a surface (32A) of an air barrier film (32) on a passenger compartment outer side toward a pillar garnish (14) to the pillar garnish (14). Consequently, even in a case where the water (W) has flowed on the surface 32A of the air barrier film 32 on the passenger compartment outer side toward the pillar garnish 14, this water guide portion (34) guides the water (W) to the pillar garnish 14, so the water (W) can be inhibited from reaching an end (28A) of an upholstery material (28) on the pillar garnish (14) side. Because of this, the water (W) can be inhibited from seeping out to a passenger compartment inner side of the upholstery material (28), so the attractiveness of the ceiling material (12) can be inhibited from deteriorating.