To provide a folding table having a thin thickness in a folded state and being prevented from clattering of the folded table legs.

A pair of flat top pieces 2a constitutes the flat top 2, and are blow-molded plastic resin plates of identical shapes. The pair 2a are connected each other with hinge fittings 4 to be folded. On the back sides of the flat top pieces 2a, the dent receptacles for the upper legs 13 and those for the lower legs 16 are situated. In the upper receptacle 13, the upper legs 5 and 6 are to be contained, and in the lower receptacle 16, the lower legs 7 are to be contained. On the backside of the flat top 2a, the dents 18 for containing parts are situated. In the dents 18 for containing parts, bolts 31 and nuts that are the connecting parts are to be contained. The dents 13 for containing upper leg are situated circularly along the peripheral of the back side of the flat top, and the dents constitute a reinforcement structure together with plural numbers of the reinforcing dents 30 and 31.