To provide a power generating device using an impeller capable of efficiently generating power regardless of conditions of location based on natural environments such as wind directions and wind power.

This power generating device 10 is provided with an air current passage 12 in a vertical direction enclosed with a wall body 11, an impeller 13 provided in the air current passage to be rotated by upward air currents, and a power generator 15 interlocked with a rotation part of the impeller to be actuated. The impeller 13 is rotated around a rotation axial center that is extended in a vertical direction. The air current passage 12 is enclosed with the outer wall 11 in a cylindrical form provided with a window 30 that can be opened and closed. The outer wall 11 and the air current passage 12 can be integrally composed with a building.