An optical deflection device having: a rotor unit including a rotary polygon mirror having a plurality of mirror surfaces on the side surface portion and a holding member holding the polygon mirror; an air dynamic pressure bearing including a rotary bearing member to support the rotor unit and a fixed bearing member rotatably supporting the rotary member; and a stator unit which supports the fixed bearing member, including a winding coil oppositely arranged to the magnet, wherein prior to an assembly process, the adhesive agent layer is formed between the outer peripheral surface of the rotary bearing member and the inner peripheral surface of the holding member, the holding member and the rotary bearing member are set at the following condition, (the inner diameter of the holding member before the assembling)≧(the outer diameter of the rotary bearing member before the assembling).