Providing a retrofocus lens system and an image-taking device having small variation in aberrations upon focusing on a close object with a high imaging magnification. The retrofocus lens system includes, in order from an object, a first lens group G1 having negative refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power. Upon focusing from infinity to a close object, the first lens group G1, the second lens group G2, and the third lens group G3 are moved to the object such that a distance between the first lens group G1 and the second lens group G2 increases, and a distance between the second lens group G2 and the third lens group G3 decreases.