To provide a lightning protection facility for a seismic isolation building, having a seismic isolation unit for controlling earthquakes or vibrations due to winds from thunderbolt.

The lightning facility in the seismic isolation building includes a grounding electrode 50 which makes lightning current grounded to the ground; a first terminal box 60 jointed to the grounding electrode 50 and a foundation part column main reinforcement 21, a lightning receiver 80 for catching thunderstroke; a second terminal box 70 connected to the first terminal box 60 and a bottom column main reinforcement 91; a foundation part beam main reinforcement junction 110 for electrically and mechanically jointing a foundation part beam main reinforcement 31 and a foundation part quadrature beam main reinforcement 33; a foundation part steel rod junction 40 joined electrically and mechanically to the foundation part beam main reinforcement 31 and the foundation part column main reinforcement 21; a bottom beam main reinforcement junction 111 electrically and mechanically jointed to a bottom beam main reinforcement 101 and a bottom quadrature beam main reinforcement 161; a bottom steel rod junction 106 electrically and mechanically jointed to the bottom beam main reinforcement 101 and an intermediate part pole main reinforcement 93; and a lightning receiver connection wire junction 82 electrically and mechanically jointed to the lightning receiver 80 and an upper column main reinforcement 95.