The most part of the paper was written at Osaka City University, and it was
accomplished at Kyoto University. I am heartily grateful to the colleagues for
their help. All the essential ideas came to me during my stay at the Institute
for Advanced Study, and the preparation for the paper was done there. I express
my gratitude to their excellent hospitality. I also wish to acknowledge National
Scientific Foundation for a grant DMS 9729992, although any opinions, findings
and conclusions or recommendations expressed in this material do not necessarily
reflect the views of the National Science Foundation. I thank the financial supports
by Japan Society for the Promotion of Science and the Sumitomo Foundation.
I am indebted to many people. I express my special thanks to Mikiya Masuda
for his encouragement and support. I would like to thank Yoshifumi Tsuchimoto
and Akira Ishii for their constant encouragements since my undergraduate student
days. I owe much thanks to Tomohide Terasoma who informed me of various
things. I am also grateful to Terasoma's family for their kindness. Thanks are
due to Masaki Kashiwara for some useful information. Mark Andrea de Cataldo
attracted my attention to Hodge modules and a decomposition theorem of perverse
sheaves. I also appreciate his great tolerance for my lack of communication ability.
Much part of this paper is a result of the effort to understand the work of Carlos
Simpson, especially  and . One of his conjectures in  made me start
to study tame harmonic bundles. Claude Sabbah kindly informed of the revised
version of his paper . I am glad that our works are cooperative in a solution
of the regular holonomic version of Kashiwara's conjecture. I warmly appreciate
Pierre Deligne for some conversation. Very special thanks go to Kari Vilonen for his
interest and encouragement to this work. I am grateful to the referee for his useful
advice and for his effort to read this quite long paper. I also wish to express my
gratitude to the referee of my previous paper  for his kind and useful comments.
I would like to dedicate this paper to Kenji Fukaya. I hope that the paper is
eligible for it.