A set of a yellow toner, a magenta toner, a cyan toner and a black toner is disclosed. Each of the color toners contains a colored particle and cerium oxide particles, the colored particle containing an amorphous polyester resin, a crystalline polyester resin, a colorant and a releasing agent; and the yellow toner contains C.I. Pigment Yellow 74, the magenta toner contains C.I. Pigment Red 122 and C.I. Pigment Red 238, the cyan toner contains any one of C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2 and C.I. Pigment Blue 15:3, and the black toner contains carbon black and any one of C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2 and C.I. Pigment Blue 15:3.