The story of FinnSonic Oy began in 1979. At that time, the Tolkki brothers from Lahti and Peter Wagner, of German origin, founded Oy Ultrasonic Finland Ab. The company's business idea was to manufacture and sell ultrasonic cleaners for the Finnish market and for export. The company first operated in Lahti, on Vipusenkatu.

The company's first product was a small ultrasonic cleaner with an orange plastic shell, which was sold in Germany and Australia in addition to the domestic market.

The 80s saw the start of heavy investment in product development. Already, the first fully automated washing lines were delivered. The company was renamed FinnSonic Oy in 1989.

In the 21st century, the focus was on modular, customized ultrasonic cleaning lines. Today, FinnSonic is also developing fluorescent penetrant inspection lines for the aerospace industry.