To provide an assembly of a grinding wheel and a holder for a surface grinder, and grinding wheel segments, capable of performing grinding at high efficiency, and capable of obtaining the high precise finished surface (a surface having higher smoothness) even if grinding is performed at high efficiency.

In an assembly of a grinding wheel provided with grinding wheel segments in recessed parts 1A on the outer peripheral surface of an annular holder 1 and a holder, each grinding wheel segment T is provided with grinding surfaces having different grinding performance on the grinding wheel part T2 on the annular holder central side and the grinding wheel part T1 on the annular holder outer peripheral side. The grinding wheel part T1 on the annular holder outer peripheral side may have grinding performance higher than that of the grinding wheel part T2 on the annular holder central side.