The Office of Industrial Economics (OIE) reported that the manufacturing production index (MPI) in June rose 4.7% year-on-year to 115.9, helped by higher production of cars, engines, sugar, air conditioners, plastics and electronic parts.
The MPI increased for a 14th straight month as shipments to the US in June stood at US$2.49 billion (82.8 billion baht), marking an all-time high.
In addition, the Consumer Confidence Index and Thai Industries Sentiment Index hit their highest points in 40 and 42 months, respectively.
Nattapol Rangsitpol, director-general of the OIE, said the MPI rose by 3.6% in the second quarter and 3.9% from January to June.
Overall utilisation rate in June stood at 69.04%, little changed from May's 69.82%.
Mr Nattapol said the output of pickups, diesel engines and passenger cars under 1,800cc increased by 11.6% last month in line with the country's healthy economy, and auto production saw positive momentum in domestic sales and car export in the same month, rising by 22.9% and 5.8%, respectively.
Sugar output increased 78.9% in June thanks to a delay in the 2017-18 sugar-crushing season.
The delay brought expanded sugar cane plantation and better weather, yielding a larger crop.
Air conditioners and related parts saw 13% growth in June, driven by local distribution, which was up by 45.8%.
"Manufacturers have stimulated the market with promotional campaigns and new innovation for air conditioners in a bid to attract buyers to replace old ones," Mr Nattapol said. "Product sales in neighbouring countries also performed very well last month, with a 15.5% rise in exports, mainly to Vietnam and Indonesia."
For plastics, output expanded by 8% in June from polypropylene and linear low-density polyethylene.
Mr Nattapol said the electronics sector grew by 6% last month in line with the growth of electronics products worldwide, particularly for high technology such as integrated circuits, smartphones and tablets.
Moreover, hard disk drives have been developed to support cloud storage, and this sector is improving electronic semiconductors for smart watches and light-emitting diode screens.
The OIE expects the MPI for 2018 to rise 2.5-3%, compared with an increase of 1.6% to 112.31 points in 2017.