To provide a building capable of improving daylighting property of a room arranged inside an upper story part of a building body.

A sloped roof 30 arranged at an upper part of a lean-to part 20 includes: a roof construction part 31 having roof surfaces 31b, 31c at both sides of a ridge part 31a; a shed roof part 32 arranged apart from one roof 31b; and an opened part 33 formed between the one roof 31b of the roof construction part 31 and the shed roof part 32. A roof balcony 22a is arranged below the opened part 33, and a first opening part 23a is formed at a wall 23 between the roof balcony 22a and the building body 10. In the first opening part 23a, the upper part of the first opening part 23a is arranged at a height above the extension line L of the one roof 31b of the roof construction part 31 in a side view. Accordingly, sunlight is introduced into the inside of the building body from the first opening part.