To provide a fire-resistant PV roof board assembly which can easily be attached directly to any supporting surface of a sloping roof, etc.

The fire-resistant PV roof board assembly includes both a PV assembly 95 equipped with a PV body 20, a fireproof shielding 90 and a connecting member for connecting this fireproof shielding to the bottom of the PV body, and a supporting/mutual engaging assembly 97. The supporting/mutual engaging assembly has a vertical support member 122 mounted on the PV assembly to support this PV assembly on the top of supporting surface, an upward interlock member 148 arranged towards an upward PV edge, and a downward interlock member 150 arranged towards a downward PV edge. The upward interlock member of one PV roof board assembly can mutually be engaged with the downward interlock member of the other adjacent PV roof board assembly.