To provide an exterior wall structure of a building, which allows flexibility on a piping and wiring route to be increased, when exposure of piping and wiring arranged along an exterior wall is prevented.

A projected corner cover 51 is provided extending over the outdoor sides of both exterior wall portions 22a and 22c forming a projected corner portion 31, in a south-side exterior wall portion 22 of a building 10. A piping installation space 77 for arranging air-conditioning piping 48 of an air conditioner is formed between the projected corner cover 51 and both the exterior wall portions 22a and 22c.