A locking member for a loose-leaf binder includes a member having an integrally pivoted portion pivotally mounted in a first actuating member, an engaging projection which engages with an engaging recess of a second actuating member to prevent movement of the second actuating member. An elastic portion which abuts against an upper surface of a first base plate to urge the engaging projection to the engaging recess, first finger hooking portion, whereby under a condition where the binder rings are closed, movement of both the base plates are prevented against an opening forces acting upon the binder rings. When first finger hooking portion is pushed toward second finger hooking portion, the engaging projection is disengaged from the second actuating member against the elastic force of the elastic portion, and both of the base plates are then moved in such directions as to open the binder rings.