In ultra-precision machining for micro channels, deformation occurs with high frequency. A high aspect ratio, high cutting speed, high feed rate, etc. all lead to deformation. Several studies on the deformation of the machined part of a workpiece have been conducted, but almost all of them have focused on experimental and finite element analyses, which take time and money. This paper presents a theoretical prediction solution for the deformation of the micro channels. To obtain maximum principle stress and deflection of micro rectangular pattern, the model used was a cantilever beam with a distributed load. Furthermore, for verifying this solution, experiments have been carried out to rectangular patterns by diamond turning. The maximum error between the predicted deformation and experimental deformation was approximately $5{mu}M$, which means that this prediction solution works well.