The article explores the relationship between idiosyncratic risk and total rate of return in the Seoul office market. By analyzing different districts, it was found that the CBD area tends to have low risk-low return, while the YBD area shows high risk-high return. Additionally, the ETC district has higher total risk compared to GBD, but lower idiosyncratic risk. The study also reveals that growth rates in excess return vary across districts. Finally, the research confirms the presence of idiosyncratic risk in the Seoul office market and highlights the statistical significance of the relationship between idiosyncratic risk and return on investment.