Direct observation of the domain wall structure in real‐size Permalloy overlay bars on the glass substrate has been made. This has been achieved by the application of the Interference Contrast Technique after Nomarski. The experimental measurements of the lateral displacement of the 180° domain wall due to the application of an in‐plane field have been taken and compared to the theoretical results obtained by the domain wall model. The overall experimental observation and results obtained confirm this type of device modelling.