Home fans booed their team off the pitch after a ragged performance by Leroy Rosenior's Gulls.
New Dale signing Chris Dagnall fired his first goal for the club when he stabbed a Gary Jones cross home at the near post in the 29th minute.
But it took a series of fine saves by Dale keeper Matthew Gilks to keep his side in contention in the early stages.
Rosenior had seen enough by half-time, taking off Matthew Hewlett and sending on tall Frenchman Morike Sako in midfield.
But worse was to follow three minutes into the second half when Rickie Lambert flicked the ball on for Jones to make it 2-0 with a left-foot shot from 12 yards.
After another brilliant save by Gilks, Sako gave Torquay some hope with a diving header from Martin Phillips' right-wing cross in the 55th minute.
But Lambert wrapped it up for Rochdale in the 66th minute. Dagnall had a shot blocked but the ball broke for Lambert 25 yards out and he drove a powerful shot past Torquay keeper Andy Marriott.
Torquay, who had taken Premiership Birmingham to an FA Cup replay recently, looked a thoroughly dispirited side in the closing stages.
And Rochdale were unlucky not to stretch their lead through two efforts by substitute Blair Sturrock in the closing stages.
It was only Rochdale's fifth win in 38 visits to Plainmoor but it left Torquay with only three home wins this season.
And Stockport's surprise win over promotion-chasing Grimsby dropped the Gulls into the bottom two.