The imaging condition acquisition unit acquires a first imaging condition as an imaging condition for imaging an observation object by using an endoscope. The index-value and imaging-condition storage unit stores correspondence between the imaging condition, and, as an index value relating to a structure of an observation object, a plurality of index values including a first index value acquirable under the first imaging condition and a second index value non-acquirable under the first imaging condition but acquirable under a second imaging condition. The imaging condition extraction unit refers to the index-value and imaging-condition storage unit and extracts the second imaging condition. The guidance display unit displays guidance indicating that the second index value is acquirable under the extracted second imaging condition.