The silicon carbide filter is used to suppress the particulate matter emitted by diesel vehicle. However performance of the filter is changed by deposition of particulate matter. Therefore it is necessary to observe the inside of the filter to develop the filter optimally. This work proposes method of 3D-Neutron Computed Tomography using I-MAP and TV method to observe the inside of the silicon carbide filter. We compared the proposed method with the conventional method by simulation.