how can i bring my family to japan?

if i am permanently working as a nurse in japan how can i bring my husband and our son with me?

I think that would be no big deal, because you are having a working visa (haven`t you?) and your husband can get because of that a spouse visa.

it is called
Spouse or Child of Permanent Resident

http://www.mofa.go.jp/j_info/visit/visa/05.html

but what will he do in japan? does he has any job opportunities?
can you both speak japanese?

I guess, because of your question, that you don`t have any japanese roots....

If you are working as a nurse in Japan (and getting that job would be quite a hurdle to overcome to start with) you could bring your husband and child on dependent visas- spouse visas are for people married to Japanese nationals, and as a working recently arrived here you would not be a permanent resident.

Supporting a family of three on a nurse's pay sounds very challenging if not impossible. If your husband has a university degree and/or skills/experience in useful areas then he can get a working visa of his own and work full time- on a dependent's visa he can only work part time.

If you are a non-Japanese on a work-permitting visa status, your husband and son (provided he is under a certain age - I am not sure but maybe 16 or 18 or so) can apply for and stay in Japan on "Dependent" status. For those on Dependent visa, work is permitted only upon a separate permit and on part-time.