I assume that you are asking if your wife could change her *Status of Residence* from "Temporary Visitor" (which includes Tourists) to one that of a "Dependent".

The answer for that is "Yes, you can." However, she will need to get a **Certificate of Eligibility** (CoE) that is issued within the validity of her "Temporary Visitor" *Status of Residence* when she makes the application for the change. (Whethere or not it gets approved though depends on the Immigration Officials.)

See [related post][1] and links below.

[Application for Certificate of Eligibility][2]

[Application for Change of Status of Residence][3]


  [1]: https://expatriates.stackexchange.com/questions/4372/is-it-possible-to-switch-from-tourist-visa-to-other-status-while-in-japan
  [2]: http://www.immi-moj.go.jp/english/tetuduki/kanri/shyorui/01.html
  [3]: http://www.immi-moj.go.jp/english/tetuduki/kanri/shyorui/02.html