in a rolled object holdiing apparatus whose holding members hold both ends of a roll core , a roll core releasing device comprises a core pushing mechanism which in turn consists of a core pushing member and a driving means for moving the core pushing member at least in the direction of radius of the core . the core pushing mechanism is either installed in a core receiving member or in a core holding member . whether to operate the driving means for the core pushing member is controlled by a core detector in the core receiving member . with this construction , the core releasing device of the invention performs automatic and reliable releasing of the core from holding members of the rolled object holding apparatus , thus eliminating various problems experienced with conventional devices during automatic replacement of rolled objects .