A booklet page turning apparatus comprising: a feed device (2a - 2d) which is configured to feed a closed booklet to a page turning position; the booklet having a front cover (Ta), inner sheets (Tc), a back cover (Td) and a binding portion (Tb), wherein the booklet can be inserted and fed to the page turning position in a normal state, with the binding portion (Tb) facing to a first side and the front cover (Ta) facing up, or in a back cover face-up state, with the binding portion (Tb) facing to a second side opposed to the first side and the back cover (Td) facing up, a page turning device which is configured to turn, about the binding portion (Tb), a page on one surface side of the booklet fed to the page turning position by the feed device (2a - 2d); a lifting mechanism serving as a lifting device which is configured to lift the pages on the other surface side at once, which are different from the page on the one surface side turned by the page turning device, upward at a predetermined angle about the binding portion (Tb) and enables to invert the booklet; a contact roller unit which is configured to enter under the pages on the other surface side lifted by the lifting device; and characterized by comprising: a control device configured to determine if the booklet is in the back cover face-up state and, if the booklet is in the back cover face-up state, configured to turn the page on the one surface side of the booklet by means of the page turning device, to lift the pages on the other surface side at once by means of the lifting device, to let the contact roller unit enter under the pages on the other surface side after the feed device (2a - 2d) has fed the booklet so as to bring the pages on the other surface side of the booklet into contact with the contact roller unit and to fold the pages on the other surface side so that the booklet thus folded is in the normal state, and then to feed the booklet to the page turning position again. a feed device (2a - 2d) which is configured to feed a closed booklet to a page turning position; the booklet having a front cover (Ta), inner sheets (Tc), a back cover (Td) and a binding portion (Tb), wherein the booklet can be inserted and fed to the page turning position in a normal state, with the binding portion (Tb) facing to a first side and the front cover (Ta) facing up, or in a back cover face-up state, with the binding portion (Tb) facing to a second side opposed to the first side and the back cover (Td) facing up, a page turning device which is configured to turn, about the binding portion (Tb), a page on one surface side of the booklet fed to the page turning position by the feed device (2a - 2d); a lifting mechanism serving as a lifting device which is configured to lift the pages on the other surface side at once, which are different from the page on the one surface side turned by the page turning device, upward at a predetermined angle about the binding portion (Tb) and enables to invert the booklet; a contact roller unit which is configured to enter under the pages on the other surface side lifted by the lifting device; and a control device configured to determine if the booklet is in the back cover face-up state and, if the booklet is in the back cover face-up state, configured to turn the page on the one surface side of the booklet by means of the page turning device, to lift the pages on the other surface side at once by means of the lifting device, to let the contact roller unit enter under the pages on the other surface side after the feed device (2a - 2d) has fed the booklet so as to bring the pages on the other surface side of the booklet into contact with the contact roller unit and to fold the pages on the other surface side so that the booklet thus folded is in the normal state, and then to feed the booklet to the page turning position again.