<p>A wavelength plate excellent in initial characteristics and in long-term reliability and resistant to an application environment and a production environment; a first wavelength plate comprising at least two phase difference films, wherein phase difference films are not bonded to each other at a laser-beam-transmitting portion and they are bonded to each other at least part of portions other than the laser-beam-transmitting portion; a second wavelength plate comprising at least two laminated phase difference films and a glass substrate laminated on at least one surface of the laminated phase difference films, wherein phase difference films and a phase difference film and a glass substrate are respectively laminated and fixed by different adhesives selected from an adhesive (A) having a glass transition temperature of up to 0°C and a Young's modulus at 23°C of up to 10 MPs and an adhesive (B) having a glass transition temperature of at least 40°C and a Young's modulus at 23°C of at least 30 MPs (the difference in glass transition temperature between the adhesive (A) and the adhesive (B) being at least 60°C and the difference in Young's modulus at 23°C between the adhesive (A) and the adhesive (B) being at least 40 MPa).</p>
