Indonesia is an area located in the ring of fire, which was formed as a result of the interaction between four plates, namely the Eurasian Plate on the south, the Eurasian Plate on the, the Philippine Plate, and the Pacific Plate on the northeast. The interaction between these plates causes Indonesia to have many active volcanoes and experience many geological natural disasters. In the tomographic inversion process, ill-condition problems are often found in matrix making. Therefore, a regularization technique is needed to obtain a consistent result. The regularization technique can be done using Matlab software with a package called IR Tools (Gazzola et al., 2018). In this research, inversion techniques are used in the form of Least Square and Iteratively Reweighted Norm (IRN). This study aims to analyze the tomographic inversion code with the regularization technique using the Iteratively Reweighted Norm (IRN). In this study, two types of data were used, synthetic data and real data. Based on the results, it shows that using the Least Square method has better where the resulting checkerboard is more than adequate to reconstruct the initial velocity and amplitude model, which is described more clearly and strongly. Based on the results of the real data inversion, it shows that there is a low Vp anomaly (red) in the lower area of Mt. Merapi and Mt Merbabu. Low seismic velocity anomalies are associated with magmatic zones, partial melting, or magma reservoirs. However, there is also a high seismic velocity anomaly (blue) associated with the subduction zone of the Indo-Australian Plate to the Eurasian Plate.