Fast Aerodynamics Routines (FaSTAR) is a recent fluid dynamics software package by JAXA. It is a convenient tool for users since various solvers and automatic generation functions of grid data are provided. Although FaSTAR is one of the fastest CFD software in the world, it is still inefficient in parallel execution because of it's irregular and unpredictable data structure. The acceleration of FaSTAR using FPGAs have been exerted, and some important cores were implemented. Here, a main loop of the viscous function which occupies about 16% of total was selected as a target of accelaration, and implemented on Xilinx's FPGA Virtex-6 achived 2.3 times speed of software execution. The operational freqency was 100 MHz with 144653 slices and the resource usage was 58% for register utilization and 96% for LUT utilization. Considering the complexity of the computation, at least 2.3 times performance improvement is expected compared with the software on Core 2 Duo 2.4GHz.