The grain growth characteristics of dual-phase (α+γ) containing high Cr-steel have investigate using α-, γ-single phases and (α+γ) dual-phase of 12%Cr Steel. The heat treatment has performed at 1000-1200℃ for 1-100hr. The results are as follows : 1) The grain growth rate in (α+γ) dual phase was substantially slower than that of single grain. 2) The relation between mean grain radius γ￣ and annealing time t is, in general described as following equation : (r￣)^n-( (r_o)￣ )^n=k_n·t……(1) i) In the case of single phase of high Cr steel, Eq.(1) is described as (r￣)²-((r_o)￣)²=k₂·t and the grain growth is controlled by boundary migration. ii) In dual phase, the grain growth needs diffusion of alloying elements because the chemical composition of α- and γ- phases differs from each other. When the volume fraction of α- , γ-phase was almost equal and γ-phase in the case of 80 and 90%γ. Eq. (1) is described as (r￣)³-((r_o)￣)³=k₃·t because the grain growth is controlled by volume diffusion iii) In the case of γ-rich phase (80 and 90%γ), the grain growth of minor phase (10 and 20%α) is described as (r￣)⁴-((r_o)￣)=k₄·t because the boundary diffusion is predominent rather than volume diffusion.