System for releasable coupling of a hole saw to a drill arbor, comprising: - a drill arbor comprising an elongate drill arbor body configured at a first end to be clamped in a drill chuck of a drill; and - a hole saw adapter provided with a longitudinal bore, in which the drill arbor body can be received so that an inner surface of the longitudinal bore of the hole saw adapter is mounted slidably on an outer surface of the drill arbor body in the longitudinal direction of the drill arbor body; wherein the hole saw adapter is configured for arranging a hole saw thereon, or the hole saw adapter is integrated into a hole saw; such that the hole saw adapter is slidable on the outer surface of the drill arbor body in the longitudinal direction of the drill arbor body together with a hole saw arranged thereon or with the hole saw with the hole saw adapter integrated therein; characterized in that - the drill arbor comprises an actuator member and at least one retaining element co-acting therewith, wherein: - the actuator member is received slidably in a longitudinal bore of the drill arbor body and is slidable in longitudinal direction of the drill arbor body by means of an operating element; - the retaining element is received in a transverse bore in the longitudinal wall of the longitudinal bore of the drill arbor body and is movable in transverse direction of the drill arbor body; and - the actuator member is slidable between a first position and a second position, wherein: - the retaining element is moved outward in transverse direction of the drill arbor body by the actuator member when the actuator member slides from the first position to the second position, so that the retaining element protrudes partially from the outer surface of the drill arbor body; - the actuator member blocks in the second position thereof an inward movement of the retaining element in transverse direction of the drill arbor body; and - the actuator member allows in the first position thereof an inward movement of the retaining element in transverse direction of the drill arbor body; and wherein - the inner surface of the longitudinal bore of the hole saw adapter is provided with a recess into which the retaining element of the drill arbor can protrude. - a drill arbor comprising an elongate drill arbor body configured at a first end to be clamped in a drill chuck of a drill; and - a hole saw adapter provided with a longitudinal bore, in which the drill arbor body can be received so that an inner surface of the longitudinal bore of the hole saw adapter is mounted slidably on an outer surface of the drill arbor body in the longitudinal direction of the drill arbor body; - the drill arbor comprises an actuator member and at least one retaining element co-acting therewith, wherein: - the actuator member is received slidably in a longitudinal bore of the drill arbor body and is slidable in longitudinal direction of the drill arbor body by means of an operating element; - the retaining element is received in a transverse bore in the longitudinal wall of the longitudinal bore of the drill arbor body and is movable in transverse direction of the drill arbor body; and - the actuator member is slidable between a first position and a second position, - the retaining element is moved outward in transverse direction of the drill arbor body by the actuator member when the actuator member slides from the first position to the second position, so that the retaining element protrudes partially from the outer surface of the drill arbor body; - the actuator member blocks in the second position thereof an inward movement of the retaining element in transverse direction of the drill arbor body; and - the actuator member allows in the first position thereof an inward movement of the retaining element in transverse direction of the drill arbor body; - the inner surface of the longitudinal bore of the hole saw adapter is provided with a recess into which the retaining element of the drill arbor can protrude.