The Welsh All Blacks led 24-14 at the break after two tries from Hywel Jenkins and one from Craig Mitchell.
Bridgend closed the gap to just five points at The Gnoll when Richard Radford scored shortly after the break.
But two James Hook penalties, and further tries from Wayne Mitchell and Ben Davies took Neath clear again.
Neath have won all but one of their league games this season, and win the title with four games to spare.
They will face Pontypridd - the only side to beat them this season - in the Konica Minolta Cup on Saturday, 6 May.
Neath coach Rowland Phillips:
"You set standards, and if you're proud people like the players are, you want to live up to those standards and move on.
"We've got a blend of youth and experience which seems to be spot on at the moment.
"We've got a lot of exciting talent coming through and we're proud of that. We've developing talent to go up to the regional game and that's exactly what we're about."
Neath: Clapham, Johnston, G. Morris, W. Mitchell, S. Thomas, Hook, Roberts, P. Jones, Littlehales, C. Mitchell, Martin, Morgan, B. Davies, Jenkins, McPhail.
Replacements: G. James, A. Thomas, Pengelly, Llewellyn, McShane, Price, Howell.
Bridgend: M. Hutchings, Howells, R. Davies, Tossell, Radford, M. David, Griffiths, Voisey, Joy, Long, Alford, Evans, G. Williams, A. Williams, Whitney.
Replacements: Hearne, A. Phillips, G. Alexander, Purnell, P. Williams, Trowbridge, Roach.
Ref: Neil Ballard (WRFU).