My son is turning 4 years old now, still scared to sleep on his own bed

[hannachen]

My 4y/o son is coming to my bed after i put him to sleep in his bedroom..he sleeps quite well and then will appear next to my bed in the middle of the night at about 2-3am. my husband would pick him back to his bed as soon as he fell asleep I don’t mind if he sleep with us but i would like to encourage my son to sleep in his own bedroom at earliest age. Any idea how to deal with this?