Ion optical analysis was made for a new focusing high-energy heavy ion microbeam system connected to the AVF cyclotron (K=110) at the accelerator facility, TIARA of JAEA Takasaki. The focusing performance of the microbeam system was estimated from both the calculation up to third-order term using TRANSPORT code and the measurement of beam resolution with the secondary electron imaging. As a result, a minimum beam size was evaluated at 0.56 and 0.62 microm in FWHM for the X and Y directions, respectively. The high-energy heavy ion microbeam system seemed to have been established as designed by the calculation with the TRANSPORT code, because it was confirmed that the calculation results was fairly reproduced by the measurement result.