To provide a structure enabling reinforcement as it is without changing the connection between an existing base stone and a placed post.

A footing concrete 6 is laid adjacently to the base stone 2, and base metal pieces 8 are placed using anchor bolts 7 fixed to the footing concrete 6. The post 1 erected on the base stone 2 is held by holding parts 4 of holding metal pieces 3 by the intermediary of packing materials 11. A plurality of pairs of parallel arm plates 5, 5 are projectingly arranged on the holding metal pieces 4 and around the post. A pair of parallel receiving plates 9, 9 of each of the base metal pieces 8 arranged to be corresponding to each pair of the parallel arm plates 5, 5 abut on the parallel arm plates 5, 5 in alignment. Each of the packing materials 11 is interposed between the two abutting parallel plates, and connecting reinforcing plates 10 are brought into contact with the outer side faces of the two abutting parallel plates, which are fastened with a fastener 12, so that the holding metal pieces 3 and the base metal pieces 8 may be respectively connected and fixed together.