The death during clashes between police and protesters on Friday raised the number of those killed during protests that started in October to at least 27.
The man who died was 40 years old and was electrocuted after falling into a pit with cables during chaotic street scenes, according to police and local media.
The exact circumstances of the man's death should be clarified as soon as possible, Chile's National Institute of Human Rights said.
The death happened during a protest in Plaza Italia, a focal point of unrest in the capital of Santiago. The demonstrations started over an increase in the subway fare and eventually encompassed grievances about pensions, education, health care and other issues.
Demonstrations are frequently held on Friday, and a movie theater burned in the latest clashes.
Demonstrators made way for firetrucks arriving to fight the blaze at the Alameda Cultural Center, which also has been a staging ground for volunteer medics who treat injured demonstrators.
Firefighters said the building was badly damaged and the cause would be investigated.