PURPOSE: To maintain the high gas permeability of a building roof panel having an internal insulation material for the improvement of the insulation quality of a building roof section, and enhance durability against moisture for the prevention of a break due to corrosion or the like.

CONSTITUTION: A plurality of air vent passages 26 extended in the slope direction of a roof are formed on a surface board 20 as a panel face member fastened to an outer frame 12. At the time of assembly, the inside of the frame 12 is filled with an insulation material 18 only over the range of roof top (interior side) inner than an outer wall 28. Also, the eaves side of the frame 28 is constituted as a hollow section 40. In addition, a recessed groove 22 is formed on the external surface of an outer frame piece 12a at the end of an eaves and a through-hole 24 is formed at the recessed groove 22. As a result, efficient ventilation takes place at the hollow section 40 via the hole 24, and the face board 20 via the passages 26, respectively. Excessive moisture and dew condensation due to permeating water can, therefore, be prevented. At the same time, the durability of a roof section, in particular the eaves section against moisture can be improved and the break thereof can be effectively prevented.