A frame structure comprising a plurality of PC (precast) columns arranged in a first direction and a second direction crossing the first direction in plan view, at least one first PC beam incorporated with first main beam rebars including an upper rebar and a lower rebar each extending in a longitudinal direction of the at least one first PC beam, each first PC beam being supported by a pair of the PC columns adjoining each other in the first direction, and at least one second PC beam incorporated with second main beam rebars including an upper rebar and a lower rebar each extending in a longitudinal direction of the at least one second PC beam, each second PC beam being supported by a pair of the PC columns adjoining each other in the second direction; wherein each first PC beam is formed with first blind holes opening out from each longitudinal end surface thereof so as to each form a first joint (33, 72) for a corresponding end of the corresponding first main beam rebar, and each of the adjoining PC columns is formed with first through holes opening out opposite to the first blind holes; and wherein each longitudinal end of the first PC beam is rigidly connected to the corresponding PC column by a first rebar inserted in each first blind hole and the corresponding first through hole, the first rebar being connected to the corresponding first main beam rebar via the first joint (33, 72), and a gap defined around the first rebar in the first through hole being filled with grout; characterised in that: each second PC beam is formed with second blind holes opening out from each longitudinal end surface thereof so as to each form a second joint for a corresponding end of the corresponding second main beam rebar, and each of the adjoining PC columns is formed with second through holes opening out opposite to the respective second blind holes; each longitudinal end of the second PC beam is rigidly connected to the corresponding PC column by a second rebar inserted in each second blind hole and the corresponding second through hole, the second rebar being connected to the corresponding second main beam rebar via the second joint, and a gap defined around the second rebar in the second through hole being filled with grout; each first rebar has one end received in the corresponding first blind hole and another end received in the corresponding first through hole, and each second rebar has one end received in the corresponding second blind hole and another end received in the corresponding second through hole, and the first PC beams are rigidly connected to the associated PC columns at a different height from the second PC beams. each second PC beam is formed with second blind holes opening out from each longitudinal end surface thereof so as to each form a second joint for a corresponding end of the corresponding second main beam rebar, and each of the adjoining PC columns is formed with second through holes opening out opposite to the respective second blind holes; each longitudinal end of the second PC beam is rigidly connected to the corresponding PC column by a second rebar inserted in each second blind hole and the corresponding second through hole, the second rebar being connected to the corresponding second main beam rebar via the second joint, and a gap defined around the second rebar in the second through hole being filled with grout; each first rebar has one end received in the corresponding first blind hole and another end received in the corresponding first through hole, and each second rebar has one end received in the corresponding second blind hole and another end received in the corresponding second through hole, and the first PC beams are rigidly connected to the associated PC columns at a different height from the second PC beams.