Pre-tax profit rose 48% to ¥94.6bn (£775m).
For the full year to 31 March 2012, Komatsu is forecasting sales of ¥2050bn (£16.8bn), up 11.2% on last year.
Directors said that demand had declined in China, but held up well enough elsewhere for the company to hit the full-year targets set at the beginning of the year.
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