TOKYO, Dec 7 (Reuters) - Japanese government bond prices were steady to slightly firmer on Monday, as a drop in equities increased the appeal of the safe-haven debt instrument. But market sentiment was weighed by weak performance in U.S. Treasuries in the previous session after a disappointing U.S. jobs report boosted hopes for a new round of stimulus. Benchmark 10-year JGB futures fell 0.03 point to 151.97, with a trading volume of 22,511 lots, while the 10-year JGB yield was flat at 0.020%. Yields on the 20-year JGB and the 30-year note stood flat at 0.390% and 0.650%, respectively. The 40-year JGB yield lost half a basis point to 0.695%. At the shorter end of the market, the two-year JGB yield fell half a basis point to minus 0.140%, while the five-year yield was unchanged at minus 0.110%. Japan shares closed lower on Monday, with the Nikkei pulling back from a more than 29-1/2-year high, as investors booked profits after five consecutive weeks of gains. The Bank of Japan maintained the size of all of its JGB buying operations, purchasing 1- to 3-year notes worth 500 billion yen ($4.80 billion) and 25- to 40-year maturities worth 30 billion yen. ($1 = 104.1200 yen) (Reporting by Tokyo markets team; Editing by Rashmi Aich)