The designated acceptance period varies depending on what participant contribution you are applying for.
(1) An initial application can be made at any time. (*1)
(2) An application for amount change can be made once a year.
(3) Voluntary suspension or amount change to 0 yen is possible at any time.
(4) Resumption after suspension is possible at any time. (*1)(*2)
(*1) Application month may be limited in some plans.
For plans which allow applications on the AnswerNet, the designated acceptance period can be found on the "Application for Participant Contributions" screen.
For plans which allow applications through company, please check with your company.
(*2) The amount of participant contribution can be specified again when you apply for resumption.