The present invention relates to a doctor device for metering and/or leveling a liquid to pasty medium applied to a moving surface, the surface in the case of direct application being a paper, board or other fibrous web and in the case of indirect application being the surface of a transfer element which transfers the medium to the fibrous web. The doctor device includes a cylindrical metering rod and a pressure tube, with which the metering rod can be pressed against the moving surface for the purpose of metering and/or leveling the medium applied. Additionally, the doctor device is of modular design, having a top part and a bottom part, the top part being provided with a first holder for holding the pressure tube, and the bottom part being provided with a second holder for holding a clamping tube.