He was attacked by two males at Regent Street bus station on Sunday between 4.20am and 8am.
The victim is in hospital receiving treatment for his injuries.
A 17-year-old boy and 18-year-old man were detained by police and are currently assisting officers with their inquiries.
Jonathan Bell, the local DUP MLA, has described the attack as reprehensible.
"Like many going to church in Newtownards this morning the news filtering through of a serious assault in the early hours of this morning filled me with horror.
"It is entirely unrepresentative of the good people of this area and our thoughts and prayers are with the victim and his family."
He continued: "The Police have been active and I know they have our unequivocal support in their investigation.
"Violent crime while alien to the vast majority of people here in Newtownards must be eradicated and its unacceptable nature reflected in the sentences given by our courts."
Police are appealing to anyone who witnessed the assault or has information in relation to it to contact them.