Inspector Pearce said she would investigate the internet video - taken on a mobile phone - with a view to using it as evidence in criminal proceedings.
Two poor-quality clips were posted on the social networking site, both showing groups of teenagers being confronted by police officers in the town.
In one, a youth is seen being restrained by officers while another is removed from the scene.
One member of the group is filmed smiling at an officer as he is handcuffed and arrested.
In the second clip, police can be seen moving in to tackle a gang and trying to control the youths as they show resistance.
The videos were apparently separately uploaded in June and August of this year.
Inspector Pearce said: “It is disappointing that someone finds this something to laugh at.
“An arrest is a serious undertaking and we do not take arresting people lightly.”
West Somerset MP Ian Liddell-Grainger said: “It is glorification of crime and makes people think it is okay to get arrested, film it, and post it as a sort of hero’s charter.
“I advise people not to do this because it is not clever and in many ways makes people think it is okay to be anti-social.”
Somerset West divisional Supt Damian Kearney called on anybody who had any video footage which could help the investigation to contact police.
Supt Kearney said: “The fact that people see it as some sort of amusing part of their day to watch is concerning.
“I do not know the facts of these incidents but ultimately there is usually a victim and I would rather people’s efforts were placed on bringing offenders to justice than getting some sort of titillation by uploading it to a film-sharing website.”
- Our photograph shows a still from one of the YouTube video postings.