(require 'migemo)
;; cmigemo(default)
(setq migemo-command "cmigemo")
(setq migemo-options '("-q" "--emacs"))
;; Set your installed path
(setq migemo-dictionary
(file-name-concat (getenv "HOME")
"local/cmigemo-default-win64/dict/utf-8/migemo-dict"))
(setq migemo-user-dictionary nil)
(setq migemo-regex-dictionary nil)
(setq migemo-coding-system 'utf-8-unix)
(migemo-init)
file-name-concat
を使うといいらしい。