Food product prices also rose, to 1.6% from 1.3% the previous month. Service prices slightly accelerated, to 3.3% from 3.2% in September.
The surge in energy prices, linked to the conflict in the Middle East and soaring oil prices, remains the main driver of the increase.
This acceleration of inflation in October, linked to soaring oil prices, is in line with Bloomberg analysts' expectations.
France is close to the zone average, with a rise in consumer prices estimated at 3.8%.
Malta (2.3%), Germany (2.8%) and Slovakia (2.9%) record the smallest increases.
This acceleration takes inflation to a new three-year high in the 21 countries sharing the single currency.
Consumer prices rose by 4% in October in the euro area, after 3.8% in September, according to a first estimate from Eurostat published Wednesday. According to Eurostat, energy prices increased by 20.8% in October, compared with 18.9% the previous month.