An optical pickup device or an optical disk device includes: a light source 11 that emits a laser beam toward an optical disk 25; an optical receiver 18 that detects light reflected from the optical disk 25; and an astigmatism-generating element 31 that generates light used for focus control in a condition where a focusing position on one of two perpendicular cross sections including an optical axis of the light reflected from the optical disk 25 is located ahead of the optical receiver 18 and a focusing position on the other cross section is located behind the optical receiver 18. The astigmatism-generating element 31 is a Fresnel mirror 31a configured to include a plurality of reflecting mirrors, and an imaginary surface 31d that connects the tips of the reflecting mirrors is curved in a concave shape toward a light incidence side.