The present invention relates to a sputtering target, which comprises a zirconium oxide as a sputtering material, wherein the zirconium oxide has an oxygen deficiency, compared to the oxygen content of its fully oxidized form, of at least 0.40 wt %, has a total amount of metal elements other than zirconium of less than 3.0 wt %, based on the total amounts of metal elements including zirconium, and has an X-ray powder diffraction pattern having a peak P1 at 28.2°+/−0.2° 2-theta, a peak P2 at 31.4°+/−0.2° 2-theta, and a peak P3 at 30.2°+/−0.2° 2-theta.