To provide a structure for partitioning a common space without requiring large connecting strength between a pole and a beam, in the structure for partitioning the common space constituted by connecting the beam to upper ends of a plurality of vertically rising poles.

The upper end and the lower end of the pole 1 are fitted and connected to caps 20 and 20 installed on a ceiling 5 and a floor surface 9. The pole 1 forms a cylindrical cross section, and has a groove 8 on a side surface. Auxiliary grooves 12 and 12 are formed on both inside surfaces of the groove 8 by making a pair. A fitting member 10 is fitted in the auxiliary grooves 12 and 12, and the beam 2 is engaged with and supported by a bracket 6 by nipping sandwiching parts 16 and 16 in the vicinity of an inlet of the groove 8, by threadeing and fastening a screw 14 inserted from the bracket 6 arranged on the pole side surface, with and to a screw hole 15 of the fitting member 10.