Abstract: An automatic cop changing device for a weaving machine in which a shuttle carrying a cop consisting of a bobbin around which a weft is wound is reciprocated between warps so as to weave the weft between the warps, comprising: a cop positioning unit for securing the shuttle stationary near a terminal point of its reciprocating movement when the weft of a current cop mounted on the shuttle is consumed by more than a precribed amount; a cop storage unit for storing a plurlaity of new cops; a robot arm carrying a weft gripping hand for drawing the weft from the current cop and a weft from one of the new cops stored in the cop storage unit, and crossing the two wefts, a cop engaging hand for moving the cop in the shuttle between its upright position and its retracted position, and a cop gripping hand for removing the old cop from the shuttle and carrying the new cop into the shuttle; a weft tying unit for tying the crossed part of the wefts; and a weft trimming unit for trimming an extraneous part of the tied weft