PURPOSE: To provide an explosion-proof hatch cover made of fiber reinforced synthetic resin in order to overcome the disadvantage of the conventional explosion-proof hatch cover made by a steel plate.

CONSTITUTION: A cover 3 is adapted to cover above an explosion-proof rapture disc 6 stretched on an opening area 5 of the top surface of an explosion-proof hatch 2 and formed by fiber reinforced synthetic resin. The peripheral edge area of the cover is fitted to a hatch combing 4 of the explosion-proof hatch 2. As the cover 3 is made of fiber reinforced synthetic resin, the cover 3 is excellent in corrosion resistance and light-weighted. As it is excellent in corrosion resistance, the maintenance such as paint mending painting for the cover 3 is not required, and as it is light-weighted, it is easy to handle the cover 3, and if the cover 3 is scattered at the time of explosion, there is no fear of damaging the surroundings.