Fermentation by the solid state fermentation (SSF) technique is an alternative method that may increase bioactive compounds and their functionality due to enzymatic activities. This study evaluated the effect of the fermentation time of black rice bran on the bioactive compound profile and the antioxidant and anti-α-amylase activities of the compounds. Fermentation was performed by using Rhizopus oligosporus (R. oligosporus) for 0, 24, 48, 72 and 96 hours. Fermented rice bran samples were collected every 24 h. The results showed that the bioactive compounds in black rice bran significantly increased (p < 0.05) during fermentation. Further significant increases were found for DPPH free radical scavenging activity (76.91 ± 0.06%) and α-amylase inhibition (73.05 ± 0.25%) in fermented (96 h) black rice bran compared to those in non-fermented bran (0 h). It was confirmed that fermentation had a significant effect on increasing the amount and activity of bioactive compounds in black rice bran.