The orientation state of crystal grains of thin film materials determines various electrical, magnetic, mechanical and optoelectric properties. Random orientation, fiber texture, and epitaxial alignment are generally distinguished as types of crystal orientation state. Also, specific combinations of single crystal substrates and their surface treatment and film material sometimes show a more complex state of orientation, such as fiber texture or epitaxial alignment that is lying off-normal to the sample surface. In-plane pole figure measurement, a type of pole figure measurement performed by a goniometer equipped with an in-plane arm, allows the recording of a complete pole figure and the detection of diffraction signals from thin films with a relatively small thickness. This helps to evaluate thin film materials with complex orientation state.