[en] The TIARA facilities (Takasaki Ion Accelerators for Advanced Radiation Application: TIARA) was constructed at Takasaki Radiation Chemistry Research Establishment (presently, Takasaki Advanced Radiation Research Institute) under the 6-year program from 1988 in order to promote effective use of ion beams. The first phase of the construction including a K110 AVF cyclotron and a 3 MV tandem accelerator was complete in 1991, and the second phase including a 3 MV single-ended accelerator and 400 kV implanter in 1993. Large AVF cyclotrons have been used mostly for fundamental nuclear physics and medical applications of radiation therapy and radioisotope production so far. The JAEA K110 AVF cyclotron is the first one dedicated to R and D in materials science and other irradiation purpose. This cyclotron facility consists of three external ion sources, an injection line, a K110 AVF cyclotron, eight main beam transport lines, and a control system. The first beam, 50 MeV ⁴He²⁺, was extracted from the cyclotron in March 1991. This report describes an outline of the K110 AVF cyclotron system and results of performance tests. (author)