Increasing the strength of materials is effective in reducing weight and boosting structural part performance, but there are cases in which the residual strain generated during the process of manufacturing high-strength materials results in a decline of durability. It is therefore important to understand how the residual strain in parts changes depending on processing conditions. In the case of connecting rods, because the strain load on the rod rib sections is high, it is particularly necessary to clearly understand the distribution of strain in the ribs. However, because residual strain is generally measured by using X-ray diffractometers or strain gauges, measurement positions are limited to positions close to the surface layer of the material. Neutron beams, however, have a higher penetration depth than X-rays. The research discussed in this paper conducted non-destructive residual strain measurements in the interior of connecting rods using the neutron beam line at Oak Ridge National Laboratory’s NRSF2, measuring the diffraction peak position of the ferrite phase. Using connecting rods manufactured under conditions that resulted in differing rates of deformation when the rods were processed, it was possible to examine the strain distribution in the rob interiors, and thus gain a clear understanding of differences in rib strain. In addition, it is known that the peak beam width, which is also obtained during measurements, indicates the size of crystallites in the structure, suggesting that it will also be possible to obtain data concerning the nano-structure of parts, which is necessary when conducting research on strong processing.