Device for locking the connection of a heddle (40) to a harness cord (50) comprising a heddle side and a harness cord side, wherein the device is composed of at most two different components, the device having a diameter on the heddle side and/or on the harness cord side which decreases towards the end. The device is releasable and recloseable, allowing the device to be reused. The said components are made from a plastics material which has a high wear resistance. The device is provided over virtually its entire length with a continuous passage (4) for guiding a heddle and a harness cord.