A little bit of extra information...
First, Nicolas and Marsokot gave great explanations. Sanja's answer is wrong - perhaps she is confusing "Yes, he has" with "yes, he had (a good job)".
I wanted to add that you can also use "do / does" with "have / has" in a way that adds emphasis. For example:
Q: Does he have a good job?
A: Yes, he does.
A: Yes, he has a good job.
A: Yes, he does have a good job! ("does" gives emphasis here, and we switch back to "have" in place of "has"). Then you could say, "And I'm so happy about it! He was unemployed for six months, and he had no money to buy food, but now everything is much better!"
Q: Do you speak French?
A: Yes, I do.
A: Yes, I speak French.
A: Yes, I do speak French! (emphasis) Then you might say, "That's really weird that you asked, because I've been looking for someone with whom I can speak French!"
Q: Do you have a pen?
A: Yes, I do.
A: Yes, I have a pen.
A: Yes, I do have a pen! (emphasis) Then, you might say, "That is so strange, because I usually never carry a pen with me"