We investigated the response of soil respiration (R_S) to soil warming in cool-temperate deciduous broad-leaved mature forests dominated by Quercus crispula in Takayama (TKY, 36˚08´N, 137˚25´E) and Tomakomai (TOEF, 42˚40´N, 141˚36´E), which belong to the JaLTER network. The experimental soil warming systems were established using heating cables in 2011 for TKY and 2007 for TOEF and automatically warmed up soil temperature by 3˚C. Daily mean R_S of mid and late growing seasons were measured using portable IRGA CO₂ sensors in Aug. and Oct., 2012. Warming treatment enhanced R_S by 9.1% in TKY and 10.0% in TOEF at mid-growing season and by 15.7% for TKY and 64.3% for TOEF at late growing season. The Q₁₀ values as temperature sensitivity of R_S were 2.89 and 2.64 in control and warmed plots at TKY and 2.44 and 1.55 in control and warmed plots at TOEF, respectively. Temperature sensitivity of R_S acclimatized under warming treatment and acclimatization was greater in TOEF than in TKY. This preliminary study demonstrated the warming effects on R_S in two cool-temperate forests and differently derived Q₁₀ values will be used to model future carbon budget of forest ecosystems.