An image processing apparatus configured to process a tomographic image of an object to be examined, includes: a processor； and memory storing computer readable instructions, when executed by the processor, causing the image processing apparatus to: set a reference line, which is used as a reference for setting a cross sectional position, on a front image of the object, the cross sectional position being one of a position where a two-dimensional tomographic image is acquired from three-dimensional data of the object, and a position where measurement light for generating a tomographic image is scanned； and set the cross sectional position having a predetermined angle as an angle relative to the set reference line.
