An oxide sintered body having zinc oxide as a main component and containing magnesium, and a transparent conductive substrate are provided, and an oxide sintered body having zinc oxide and magnesium, wherein content of magnesium is from 0.02 to 0.30 as atom number ratio of Mg/(Zn+Mg); an oxide sintered body having zinc oxide, magnesium, gallium and/or aluminum, wherein content of gallium and/or aluminum is over 0 and equal to or lower than 0.09 as atom number ratio of (Ga+Al)/(Zn+Ga+Al), and content of magnesium is from 0.02 to 0.30 as atom number ratio of Mg/(Zn+Ga+Al+Mg); a target obtained by processing these oxide sintered bodies; and a transparent conductive film formed on a substrate by a sputtering method or an ion plating method, by using this target.