To realize a substrate holding apparatus for a semiconductor aligner, etc., whereby the influence of dust stuck on its contacting surface for holding such a substrate as a wafer is reduced and the dust can be removed easily and quickly even when sticking on the contacting surface.

Arranging a plurality of spherical bodies 2 in a recess 1a of a chuck main body 1 of a substrate holding apparatus, a substrate 8 is supported on the apexes of these spherical bodies 2 to hold it on the chuck main body 1 by sucking. Disposing in the recess 1a of the chuck main body 1 movably a retainer 3 for retaining the plurality of spherical bodies 2 at a predetermined space, the retainer 3 is configured to be operated movably by a driving mechanism 6. The clearance between each spherical body 2 and each hole 3a of the retainer 3 is provided with a member 4 used both as a cover and as a dust remover and contacted pressingly with the surface of each spherical body 2. Each spherical body 2 rotates in response to the movement of the retainer 3 to change suitably the place of the apex portion of its contacting portion with the substrate 8. Also, dust 9 sticking on each spherical body 2 is scraped off by the member 4 used as a cover and as a dust remover to make the dust 9 removable quickly.