A device for unlocking a system for closing a container by means of a tie, such as a rope or strap, in particular a tie tensioned between closing eyelets, includes a cutting tool (O) capable of cutting the tie in order to unlock the closing system. It also includes an actuation member linked to the cutting tool, the actuation member being capable of being manipulated manually by a user in order to cause the cutting tool (O) to move into a position for severing the tie.