The self-opener closure consists of a pour-out spout (2) which may be sealingly assembled onto a composite packaging or onto a container spout or bottle spout to be closed with film material, of an associated rotary cap (1) as well as a self-opener sleeve (3) arranged within the pour-out spout (2) which may be set into rotation by the rotary cap (1). Force transmission means and guide means are formed on these three elements. These cooperate with one another such that on rotating the rotary cap (1) in the opening direction for the first time the self-opener sleeve (3) firstly in the pour-out spout (2) may be pushed vertically downwards and subsequently may be rotated by approximately 360° in the horizontal. Because the self-opener sleeve (3) at its lower edge and projecting from this comprises a single, combined piercing and cutting member (9) the film or the composite packaging is first reliably pierced and afterwards a disk is cut cleanly out of it and pivoted downwards.