An endoscope system includes a correction-value calculating unit that calculates a correction value of data to be used for calculation of biological information or the like； an index-value calculating unit that calculates one type of index value or a plurality of types of index values to be used as a determination reference for determining whether the correction value is to be calculated or whether the correction value is to be used； a display unit that displays the one type of index value or the plurality of types of index values； an input unit that inputs an instruction for calculating the correction value or an instruction for executing correction by using the correction value； and a correction unit that, if the correction-value calculating unit calculates the correction value in response to the instruction for calculating the correction value or if the instruction for executing correction is issued, executes correction by using the correction value.
