A doctor apparatus is disclosed and includes a doctor roll (12) supported in a coater (1) suitable for applying coating to a paper web surface or a roll surface (4) for subsequent transfer to the paper web. The doctor includes a doctor roll (12), a support (11) for the doctor roll (12), a front support (3) for holding the roll support (11) and a rear support or retainer (18) cooperates with and helps stabilize the support (11) and doctor roll (12). The present invention minimizes the variation moving of the doctor roll (12) has on the coating on the moving surface (4), be it web or roll, and thus can improve coating quality.