An electrostatic image developer contains a toner and a carrier having a resin coating layer formed on the surface of a core material containing a ferrite component, wherein a ratio R1/R2 is from 0.88 to 0.92 where R1 is the resistance value (.OMEGA.) of the developer having a toner concentration of 2 mass % in a state formed into a magnetic brush, at an applied voltage of 10.sup.4 V/cm, and R2 is the resistance value (.OMEGA.) of the developer having a toner concentration of 12 mass % in a state formed into a magnetic brush, at an applied voltage of 10.sup.4 V/cm.