Luciano Narsingh opened the scoring after 14 minutes, coming in from the right and netting via the post, before a defence splitting exchange between Kevin Strootman and Georginio Wijnaldum resulted in the second goal nine minutes later.
Dries Mertens, Wijnaldum, Timothy Derijck and Orlando Engelaar were also on target to take PSV's league tally to 48 goals in 13 matches. Fourth placed Ajax Amsterdam are the next closest in the scoring stakes, with 31 goals.
Charlton Vicento scored a consolation goal for Den Haag.
"Our tally says everything about this team. We never settle when we are 2-0 up and today we completely dominated the match," said skipper Mark van Bommel.
PSV are top with 33 points, four ahead of Twente Enschede who travel Utrecht on Sunday. Third-placed Vitesse, on 25 points, host neighbours NEC Nijmegen.
Ajax stayed fourth with 24 points following a 2-0 win over strugglers VVV Venlo, who are 17th in the 18-team league with nine points.
Ajax, without the injured Kenneth Vermeer and Ryan Babel, displayed a lacklustre first half but broke the deadlock early after the break when Derk Boerrigter curled a free kick over the wall, while Danny Hoesen sealed the win six minutes from time. (Reporting by Theo Ruizenaar, editing by Pritha Sarkar)