PURPOSE: To arbitrarily open and close the tip half side of a surface plate and a reverse side plate, so that a commutation ticket can be thrown in automatically, and to contrive smooth entering/leaving passing at an automatic ticket barrier by forming three sides of the tip side to an open state, using them an receiving/detaching port parts of the commutation ticket, and also, arranging a tongue in the right and the left parts of the tip side, and providing the tongue with a finger opening fastener.

CONSTITUTION: At the time of opening a finger opening fastener 12, when a fingertip, etc., F of one finger of a slider role inserted from a finger insertion port 11 are allowed to slide and advanced, while opening the fork of both pieces 3, 4 extending from a base part between both front and rear rack armatures 3, 4 to an internal advance direction X, when the fingertip, etc., F reach a position immediately before the finger opening fastener 12, a fastener projecting body 13 and a recessed body 14 which are fitted and detained start to separate. When the finger opening fasteners 12 arranged in the right and the left posts are opened, both outside inflection circular arc surfaces 9, 10 of a surface plate 1 and a reverse side plate 2 return to an original style of a gentle arc. At the time of closing the fastener 12, the front and the rear rack armatures 3, 4 brought into contact with the surface in the front part of the finger insertion port 11 are inserted and held by the fingertip, etc., F, advanced and closed, while bringing them into contact with each other.