A recording tape cartridge including at least a door opening and closing an opening by rotating around a supporting shaft provided at a front wall side; an allowing portion formed in the door, which allows avoidance of contact between the door and a distal end surface of a leader tape when the door closes the opening; and a guide portion formed at the allowing portion, and abutting the distal end portion of the leader tape, and formed to be thick-walled in a direction of making the distal end portion of the leader tape move away from the side wall. When the door closes the opening of the recording tape cartridge, a predetermined clearance is ensured between the distal end surface of the leader tape and a deepest surface of the allowing portion.