Abstract: A crane apparatus of the present invention is configured to install a tower and a wind power generation system and includes an elevation unit configured to be movable upward or downward, and a crane unit configured to raise an element that constitutes the wind power generation system, in which the elevation unit includes upper and lower bases configured to switch between a state in which the upper and lower bases are supported on the tower and a state in which the upper and lower bases are movable, a plurality of posts configured to fix the upper and lower bases to each other, a lifting base configured to switch between a state in which the lifting base is supported on the tower and a state in which the lifting base is movable, and a drive device configured to change distances between the lifting base and the upper and lower bases.