Central and lateral incisors of 20, 40 and 60 age groups were bisected pararelly to long axis and middle portion of mesio-distal of teeth. And author measured the hardness of various areas in enamel and dentin with vickers hardness tester. Measured levels were divided into the labio-middle portion, middle portion of incisal edge and linguo-middle portion in enamel and dentin of all age groups. The results were as follows; 1) Total average hardness of enamel for 20, 40 and 60 age groups were respectively Hv. 366.5${pm}$5.75, Hv. 372.9${pm}$8.16 and Hv. 389.8${pm}$10.27. 2) Total average hardness of dentin for 20, 40 and 60 age groups were respectively Hv. 51.0${pm}$2.14, Hv. 54.0${pm}$1.87 and Hv. 55.3${pm}$2.23. 3) Total microhardness values in enamel and dentin of 60 age group was highered than 20 and 40 age groups. 4) The hardness values of enamel and dentin in all age groups were detected lower value on the middle portion of incisal edge than the labio-middle portion and linguo-middle portion. 5) Microhardness values of enamel was highered gradually from the dentinoenamel junction to the outer surface and it lowered at the outermost surface in all age groups. The microhardness values of dentin were the highest values at 600${mu}$ from dentino-enamel junction and the lowest values at near the pulp chamber in all age groups.