As the fire-resistance performance of high-strength concrete has emerged as a social issue and Korean Ministry of Land, Transport & Maritime Affairs has announced the standard for the fire-resistance performance of the concrete, studies to improve its fire-resistance have been conducted actively. In this paper, the study to develop high-strength concrete mixed with fiber-cocktail, a hybrid of polypropylene fiber and steel fiber was conducted. The fire-resistance test of 100MPa high-strength concrete and the analysis of steel bar temperatures for finding the optimal cross-sectional condition showed that the larger the section size is, the lower the temperature of steel bars is. It was also shown that the concrete columns with section sizes of 600mm x 600mm and 800mm x 800mm secure fire-resistance performance and the former is the optimal section size in terms of economic efficiency. The analysis of steel bar temperatures of the column having section size of 600mm x 600mm showed that the polypropylene fiber to steel fiber ratio of 1.5 to 40 (㎏/㎥) is the optimal for the fiber cocktail.