This study is to investigate experimentally residual strength properties of the high strength concrete containing the hybrid of nylon and polypropylene fiber at elevated temperature. Test results showed that specimens heated up to $300^{circ}C$ exhibited similar strength properties to the one at room temperature. This result is significantly different from previous studies. but specimens heated over $400^{circ}C$ showed dramatic decrease indicating similar tendency. For the residual strength properties, one at $300^{circ}C$ even increased 10%, which is also different from previous studies, but it significantly decreased in $400^{circ}C$ as widely expected. Melted pores by organic fibers in concrete specimens was observed with FE-SEM. For the density of concrete in elevated temperature, internal system in $200^{circ}C$ had even denser than in $20^{circ}C$, but was collapsed in $400^{circ}C$.