A developing device and image forming apparatus that can satisfy stability over time in relation to amount of developer carried, and prevent developer retention, deterioration of developer and developing sleeve adhesion, wherein the amount of developer carried per unit area on the developer carrier in the developing region is 30 mg/cm2 to 60 mg/cm2; the weight mean particle diameter of the toner is 4.5 μm to 8.0 μm; the ratio Dw/Dn of the toner weight mean particle diameter (Dw) and the number mean particle diameter (Dn) is 1.20 or less; an irregular roughness pattern having the maximum height Rz of the surface roughness of 20 to 40 μm and the mean space Sm of the roughness of 100 to 200 μm is formed on the surface of the developer carrier; and the relationship between the developing gap PG and the gap DG between the developer restricting member and the developer carrier is 1.0≦(DG/PG)≦3.0.