To provide a rooftop support structure capable of easily and accurately supporting various kinds of rooftop-installed objects such as a solar panel and sunlight warm water panel on roof tiles.

A rooftop support structure 10 comprises: support posts 13 penetrating through tiles 11 and standing on a roof board 12; and object locking means 14 mounted to the support posts 13 such that the position of the object locking means 14 can be changed in a roof gradient direction R and in the horizontal direction in order to lock a solar panel P1 to the support posts 13. The object locking means 14 includes: a slide bracket 20 mounted to a slide guide 19 supported by the support posts 13; and an attaching bracket 21 mounted to the slide bracket 20 in order to lock the solar panel P1 to the slide bracket 20. The slide bracket 20 can be displaced along the slide guide 19 in the roof gradient direction R, and the attaching bracket 21 can be horizontally displaced along the slide bracket 20.