To provide a structure and a method which can stably install solar cell panels constituting a photovoltaic power generator at a position of a predetermined height on the ground.

An installation structure of a support post 11 erected on the ground comprises: a cylindrical support post including a plurality of slits 12 in a lower part and belt pieces 13 between the slits bendable in their opening direction at starting end parts of the slits; and a cylindrical burial structure 21 positioned in the lower part of the support post and having an inclined surface 22 becoming narrower and tapered upwardly around an upper end opening part. A vertical hole 31 of a predetermined diameter is prepared in the ground and the burial structure is housed in the vertical hole; the support post is pushed onto the inclined surface of the upper end of the burial structure from above to expand the belt pieces provided in the lower part of the support post so as to be along the inclined surface, while tips of the belt pieces are pushed to the wall surface of the vertical hole; and then concrete is poured from above the cylindrical support post to fill the cylindrical burial structure and the vertical hole with concrete from the upper end opening part.