To provide a T-shaped filler welded joint and a T-shaped fillet welded panel which can sufficiently restrain welded deformation of buckling deformation, etc., at the time of fillet-welding aluminum alloy thin plates having ≤5mm thickness.

The T-shaped fillet welded joint 10 is constituted with an aluminum alloy vertical skelton 12 fillet-welded to the aluminum alloy plate 13 having ≤5mm thickness (t1) and <50t1 width W1. Then, the aluminum alloy panel 21 is butt-welded between the joints 10. This aluminum alloy panel plate 21 has <70t2 width W2 at the time of using (t2) for the plate thickness.