Operating profit was about 173 billion yen (1.08 billion pounds) for the first half, compared with an upwardly revised forecast of 145 billion yen issued in July. The average of four analysts' forecasts was 150.4 billion yen, according to Thomson Reuters StarMine.
Hitachi left its earnings forecasts for the full year to March unchanged, including its operating profit projection of 500 billion yen, citing uncertainty in currency rates, commodity prices and the global economy.
Semiconductor equipment manufacturer Tokyo Electron Ltd on Wednesday also said it beat its half-year projections and lifted its full-year operating profit forecast to 30 billion yen from 18 billion yen, citing strong orders.
The average of 21 analyst estimates from Thomson Reuters StarMine had indicated a full-year profit of 21.5 billion yen. The company last month announced an agreement to be acquired by Applied Materials.
The better-than-forecast results by two of Japan's leading technology companies mark a strong kickoff to Japan's second-quarter earnings reporting season. Canon Inc is due to report earnings on Thursday, though analysts expect a subdued result due to a weak outlook for camera demand.
Hitachi, which also gave first-half figures for revenue, pre-tax and net profit, declined to give details ahead of its full earnings announcement next Tuesday.
Japanese companies are required to disclose earnings estimates that vary by 30 percent or more from their official forecasts, so revision announcements are common as companies prepare quarterly earnings reports.
(Reporting by Edmund Klamann and Nobuhiro Kubo; Editing by Christopher Cushing)