An endoscope system (10, 11), comprising: illumination means for irradiating a subject with illumination light including a blue component and a green component; image signal acquisition means (50, 51, 44, 45, 46) for acquiring two or more color signals (B, G) having different pieces of color information by receiving and imaging return light from the subject using an imaging element; multi-color image generation means for generating a multi-color image formed from calculated values obtained by performing predetermined calculation for each pixel using the two or more color signals (B, G); and blood vessel extraction image generation means (63, 63a - 63c) for generating at least one of a first layer blood vessel extraction image, which is obtained by extracting a first layer blood vessel at a specific depth from the multi-color image, and a second layer blood vessel extraction image, which is obtained by extracting a second layer blood vessel at a position deeper than the first layer blood vessel from the multi-color image, by performing blood vessel extraction processing, which differs depending on each of a plurality of observation modes, on the multi-color image, characterized in that the blood vessel extraction image generation means (63, 63a - 63c) includes a plurality of calculated value tables (63a - 63c), which store a correlation between a mucous membrane, the first layer blood vessel, and the second layer blood vessel of the subject and the calculated values, and a blood vessel extraction image generation section that generates at least one of the first layer blood vessel extraction image and the second layer blood vessel extraction image by performing blood vessel extraction processing using a calculated value table (63a - 63c) corresponding to the set observation mode, the calculated value table (63a - 63c) is set for each of the plurality of observation modes, in each of the calculated value tables (63a - 63b), a calculated value indicating a boundary between the mucous membrane and the first layer blood vessel is stored as a first boundary value (Ls, Ls', Ls"), and a calculated value indicating a boundary between the mucous membrane and the second layer blood vessel is stored as a second boundary value(Ld, Ld', Ld"), said first and second boundary values being used to generate at least one of said first and second layer blood vessel extraction images, and the first and second boundary values differ depending on each calculated value table (63a - 63c). illumination means for irradiating a subject with illumination light including a blue component and a green component; image signal acquisition means (50, 51, 44, 45, 46) for acquiring two or more color signals (B, G) having different pieces of color information by receiving and imaging return light from the subject using an imaging element; multi-color image generation means for generating a multi-color image formed from calculated values obtained by performing predetermined calculation for each pixel using the two or more color signals (B, G); and blood vessel extraction image generation means (63, 63a - 63c) for generating at least one of a first layer blood vessel extraction image, which is obtained by extracting a first layer blood vessel at a specific depth from the multi-color image, and a second layer blood vessel extraction image, which is obtained by extracting a second layer blood vessel at a position deeper than the first layer blood vessel from the multi-color image, by performing blood vessel extraction processing, which differs depending on each of a plurality of observation modes, on the multi-color image, characterized in that the blood vessel extraction image generation means (63, 63a - 63c) includes a plurality of calculated value tables (63a - 63c), which store a correlation between a mucous membrane, the first layer blood vessel, and the second layer blood vessel of the subject and the calculated values, and a blood vessel extraction image generation section that generates at least one of the first layer blood vessel extraction image and the second layer blood vessel extraction image by performing blood vessel extraction processing using a calculated value table (63a - 63c) corresponding to the set observation mode, the calculated value table (63a - 63c) is set for each of the plurality of observation modes, in each of the calculated value tables (63a - 63b), a calculated value indicating a boundary between the mucous membrane and the first layer blood vessel is stored as a first boundary value (Ls, Ls', Ls"), and a calculated value indicating a boundary between the mucous membrane and the second layer blood vessel is stored as a second boundary value(Ld, Ld', Ld"), said first and second boundary values being used to generate at least one of said first and second layer blood vessel extraction images, and the first and second boundary values differ depending on each calculated value table (63a - 63c).