The Thai Industries Sentiment Index (TISI) increased to 93.8 points last month from 93.2 in December on big government investment projects, domestic consumption and the general election scheduled for next month.
Montri Mahaplerkpong, vice chairman of the Federation of Thai Industries (FTI), reported the figures on Thursday.
He said the business sector was concerned about the baht's continuing appreciation, the trade war between China and the United States, higher costs due to crude oil prices and interest rates.
The TISI was based on the FTI's survey of 1,207 companies in 45 industrial sectors.
Mr Montri said the TISI for the next three months was 104.1, down from 105.9 projected last month, due to the US-China trade war.