Andrew Forster, who owns the Wellington Inn, in Preston, discovered an intruder in one of the bedrooms at about 15:30 BST on Saturday.
He said a crowd gathered at the pub to help after his social media appeal before police arrived an hour later.
Lancashire Police said it regretted the delay but no patrols were available.
Mr Forster said he was shocked when the manager of the pub, who made the initial 999 call, told him police would not be responding as an emergency.
He then put a plea out on Facebook asking for help on what to do with a burglar he had trapped in the bedroom.
His friend promptly arrived - along with others - and helped him hold the door shut.
He said he was told off by a call handler when he made a second call as it was "not an emergency" and he should call 101.
Lancashire Police said the operator advised the caller they were "experiencing a high level of demand and would get someone there as soon as we could".
The force said it arrived at the pub in Glover's Court at 16:33 BST and a woman was arrested.
Mr Forster said: "I know they are understaffed.
"I'm not angry with the police but I'm angry with how they dealt with it."
The 35-year-old said the response on Facebook showed the power of social media.
"It is a lovely community pub and it was great people came here offering their support."
Lancashire Constabulary said in a statement: "We regret that we were unable to attend the incident sooner, however, unfortunately due to a busy period of demand and a number of ongoing incidents across the area there were no patrols available to attend at that time."
It added a woman had since been charged with burglary.
A pub owner who trapped a burglar posted an SOS on Facebook for help when he said police told him it was not an emergency.