Hydrolysis was applied to collagen of Yezo sika deer tendon using six proteases (pepsin, trypsin, papain, chymotrypsin, pronase E, and thermolysin). The yields of hydrolysates and its protein contents ranged from 69 to 96% (w/w) and 185.7 to 260.6 μg/mg lyophilized powder, respectively. Next, the functional properties of hydrolysates were demonstrated using a different four systems. Antioxidative activities were moderate; the hydrolysates prepared by pepsin, trypsin, chymotrypsin, and pronase E showed the same activities as 1 mM ascorbic acid. Reactive oxygen species scavenging activities were also measured. Highly scavenging activities were observed in pronase E, papain, and chymotrypsin hydrolysates. On the other hand, thermolysin hydrolysate strongly inhibited ACE activity. From the above investigation, Yezo sika deer tendon can be used as an easily accessible underutilized bioresource of natural antioxidants, ACE inhibitors, and as a possible food supplement or in biomedical fields and pharmaceutical industry.