To provide a safety fence for an opening with a floor lid which is favorable in workability, and can be easily manufactured.

This safety fence for the opening with the floor lid is equipped with safety fence structures which are arranged in such a manner as to surround four sides of the opening, respectively. Each of the safety fence structures comprises: a plurality of supports: brackets which are fixed near lower ends of the supports around the opening, respectively; and a rod which is inserted through a hole formed at each of the brackets, the one end of which is fixed to the lower end of the support at one end, and the other end of which is fixed to the lower end of the support at the other end. Each of the supports can be turned on the longitudinal axis line of the rod. A torsion imparting mechanism which is constituted so that torsion can be imparted to the rod when the support is brought down is arranged in each of the safety fence structures.