(Edited)

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, since it takes about 1-3 months to process her application, she may want to apply *also* for a **Certificate of Eligibility** (CoE) when she makes the application for the change. This is because her "Temporary Visitor" *Status of Residence* may expire while waiting for the change to be approved.

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