An endoscope system comprising: an endoscope that includes a beam light-emitting unit irradiating a subject with measurement beam light and an image pickup optical system provided in a distal end part at a position different from a position of the beam light-emitting unit and receiving light from the subject, the measurement beam light being emitted obliquely with respect to an optical axis of the image pickup optical system; and a processor device, wherein the processor device includes a processor that acquires a subject image that is obtained on the basis of the light received by the image pickup optical system and includes a beam irradiation region appearing on the subject due to irradiation with the measurement beam light, recognizes the beam irradiation region from the subject image, and causes a display to display a measurement image in which a measurement marker to be used to measure a size of the subject is displayed in the subject image on the basis of the beam irradiation region; characterized in that: the beam irradiation region of the subject image has a pattern having a specific shape that includes a white central region and a peripheral region covering a periphery of the central region and having a feature quantity based on the measurement beam light irradiated on the subject, and wherein the processor recognizes the beam irradiation region having the pattern having the specific shape; and wherein: the feature quantity is at least one of a color of the measurement beam light, a color other than the color of the measurement beam light, or luminance, brightness, chroma saturation, or hue of the measurement beam light. an endoscope that includes a beam light-emitting unit irradiating a subject with measurement beam light and an image pickup optical system provided in a distal end part at a position different from a position of the beam light-emitting unit and receiving light from the subject, the measurement beam light being emitted obliquely with respect to an optical axis of the image pickup optical system; and a processor device, wherein the processor device includes a processor that acquires a subject image that is obtained on the basis of the light received by the image pickup optical system and includes a beam irradiation region appearing on the subject due to irradiation with the measurement beam light, recognizes the beam irradiation region from the subject image, and causes a display to display a measurement image in which a measurement marker to be used to measure a size of the subject is displayed in the subject image on the basis of the beam irradiation region; characterized in that: the beam irradiation region of the subject image has a pattern having a specific shape that includes a white central region and a peripheral region covering a periphery of the central region and having a feature quantity based on the measurement beam light irradiated on the subject, and wherein the processor recognizes the beam irradiation region having the pattern having the specific shape; and wherein: the feature quantity is at least one of a color of the measurement beam light, a color other than the color of the measurement beam light, or luminance, brightness, chroma saturation, or hue of the measurement beam light.