Anyone non-thai here who applied visa for Japan?

Hello everyone, my son is now 6 months old and was born in Chiang Mai(My husband,I and my son are not Thai citizen). We just got his passport from the embassy, ​​it is blank, without any visa and stamp. I want to take him back to my country for two months to visit relatives and then return to Chiang Mai, I am on a one-year ED visa. Does my son need to apply for a separate visa when he returns to Thailand? What visa does he need? Or I could bring him back to thailand without Thailand visa for him? I hope someone with experience could give me some advice. Thank you so much!

I not thai citizen but wife and daughter they are thai citizen we plan to go back to Thailand at 2nd of November coordinator by Thailand embassy here in Malaysia they ask us to buy the tickets flight and for non thai have to book ASQ in this situation they will let wife stay with me in same from or same hotel free under government payment or will separate us

Thank you for your comments 🙂