We compared muscle oxygen saturation (SmO<inf>2</inf>) responses in several leg muscles and within a single muscle during ramp cycling exercise between elderly men (n = 8; age, 65 ± 3 years; ELD) and young men (n = 10; age, 23 ± 3 years; YNG). SmO<inf>2</inf> was monitored at the distal site of the vastus lateralis (VLd), proximal site of the vastus lateralis (VLp), rectus femoris (RF), vastus medialis (VM), biceps femoris (BF), gastrocnemius lateralis (GL), gastrocnemius medialis (GM), and tibialis anterior (TA) by near-infrared spatial resolved spectroscopy. During submaximal exercise, significantly lower SmO<inf>2</inf> at a given absolute work rate was observed in VLd, RF, BF, GL, and TA but not in VLp, VM, and GM in ELD than in YNG. In contrast, at all measurement sites, SmO<inf>2</inf> at peak exercise was not significantly different between groups. These results indicate that the effects of aging on SmO<inf>2</inf> responses are heterogeneous between leg muscles and also within a single muscle. The lower SmO<inf>2</inf> in older men may have been caused by reduced muscle blood flow or altered blood flow distribution.