Marvin Lewis doesn’t plan to leave one of the NFL’s safest coaching jobs.

The Cincinnati Bengals coach said Monday the team’s worst start in six years hasn’t diminished his commitment to getting it turned around. A 31-22 loss at Dallas left Lewis’ team at the bottom of the league, the only one with an 0-5 record. Three other teams are 0-4.

It’s a major slip from 2005, when Lewis led the Bengals to their only winning record and playoff appearance since 1991, when owner Mike Brown took over for his father.

‘‘Yes, I am very committed to doing the right thing here,’’ Lewis said, when asked if he planned to stay as head coach. ‘‘I honestly don’t think anything has ever changed here. The commitment that I made five years ago here and (again) three years ago, two years ago, whenever, is that we’d see this thing all the way through and get us back to where we were.’’

No matter how bad it gets, Lewis’ job is one of the safest around. Two years ago, he got a contract extension through 2010, virtually a guarantee that he will be around that long unless he challenges the front office. That’s how things work in Cincinnati.

Brown took control of the team after his father, Paul, died before the start of the 1991 season. The Bengals have been one of the NFL’s worst franchises over that span, managing only one winning season. Even when things have been very bad, the head coach has felt secure.

It takes more than a bad record to get a Bengals coach fired.

Sam Wyche led the Bengals to their second Super Bowl appearance in the 1988 season, losing to San Francisco. Then the Bengals slipped to 3-13 in 1991, and Wyche began questioning Brown’s roster moves and lobbying for a bigger role in decision making .

Their differences came to a head at their annual end-of-the-season meeting, where they parted ways. Brown, who functions as the de facto general manager, said he had no intention of firing Wyche, who had two years left on his contract. Brown said that Wyche resigned during the meeting. Wyche insisted he was fired.

Three months later, they reached an agreement over the final $1 million owed Wyche on his contract.

Brown hired Dave Shula and later gave him a two-year contract extension while he was in the process of losing 50 games faster than any coach in NFL history. Bruce Coslet replaced Shula seven games into the 1996 season — the last year on Shula’s contract — and stuck around until 2000, when he resigned after an 0-3 start, saving the team some money.

Brown let Dick LeBeau complete the final year on his contract in 2002, when the Bengals went a franchise-worst 2-14. Lewis was hired, led the team to that playoff appearance in 2005, and got a contract extension through 2010, providing long-term job security.

Lewis has publicly disagreed with Brown this season over the owner’s decision to bring back troubled receiver Chris Henry. If Lewis follows Wyche’s example and presses the owner for more control at the end of the season, the dynamic of their relationship could change.

For now, Lewis is immersed in changing things under the system in place.

‘‘We’ve taken some lumps this year, and that doesn’t change how I approach what I do,’’ Lewis said. ‘‘I’m excited about our football team. I actually like our football team, other than being 0-5. I like our guys. I like what we’re doing. We’re working very, very hard.’’