Needle bed for circular knitting machine, and circular knitting machine including same needle bed

To provide a needle bed for a circular knitting machine in which, without greatly changing the structures of a knitting tool and an insert piece for forming a groove for slidably storing the knitting tool, the contact area between the knitting tool and the insert piece is reduced. A needle bed which is mountable to the circular knitting machine is configured to slidably store a knitting tool in a groove of which both side surfaces are formed by opposed plate surfaces of adjacent insert pieces 50 having a rectangular plate shape, wherein each insert piece 50 has a plurality of dimples 53 formed in a short-side direction X and a long-side direction Y on the plate surfaces.