An endoscope apparatus comprising: image pickup means equipped with a color separation section that color-separates and receives returning light of light radiated onto a subject by illumination means to pick up an image of the subject; emphasis processing means that performs emphasis processing on sharpness of an image signal based on the image pickup means; storage means that stores information for modifying processing contents of the emphasis processing means according to spectral characteristics of the returning light incident on the image pickup means which differ depending on a type of the image pickup means and an observation mode; and control means that performs control of modifying the processing contents of the emphasis processing means based on the information of the storage means, wherein the storage means stores, when the observation mode is a first observation mode in which image pickup is performed under illumination of white light, information for setting an image signal to be subjected to emphasis processing by the emphasis processing means to a luminance signal and two color difference signals, and stores, when the observation mode is a second observation mode in which image pickup is performed under illumination of narrow band illuminating light, information for setting an image signal to be subjected to emphasis processing by the emphasis processing means to a luminance signal and one color difference signal, and in the first observation mode and the second observation mode, the emphasis processing means performs setting of filter coefficients according to an array structure corresponding to a pixel density of a plurality of filter elements making up the color separation section, such that an amount of emphasis when performing emphasis processing on the luminance signal in the image signal becomes greater than an amount of emphasis when performing emphasis processing on the color difference signal in the image signal over an entire frequency domain. image pickup means equipped with a color separation section that color-separates and receives returning light of light radiated onto a subject by illumination means to pick up an image of the subject; emphasis processing means that performs emphasis processing on sharpness of an image signal based on the image pickup means; storage means that stores information for modifying processing contents of the emphasis processing means according to spectral characteristics of the returning light incident on the image pickup means which differ depending on a type of the image pickup means and an observation mode; and control means that performs control of modifying the processing contents of the emphasis processing means based on the information of the storage means, wherein the storage means stores, when the observation mode is a first observation mode in which image pickup is performed under illumination of white light, information for setting an image signal to be subjected to emphasis processing by the emphasis processing means to a luminance signal and two color difference signals, and stores, when the observation mode is a second observation mode in which image pickup is performed under illumination of narrow band illuminating light, information for setting an image signal to be subjected to emphasis processing by the emphasis processing means to a luminance signal and one color difference signal, and in the first observation mode and the second observation mode, the emphasis processing means performs setting of filter coefficients according to an array structure corresponding to a pixel density of a plurality of filter elements making up the color separation section, such that an amount of emphasis when performing emphasis processing on the luminance signal in the image signal becomes greater than an amount of emphasis when performing emphasis processing on the color difference signal in the image signal over an entire frequency domain.