An A-site-ordered double perovskite BiCu3Fe4O12 was synthesized at high-pressure and high-temperature conditions. Similar to the isostructural LaCu3Fe4O12, the temperaure-induced intermetallic charge transfer between the A'-site Cu and the B-site Fe ions occurs but at higher temperature (428 K) than LaCu3Fe4O12 (393 K) does. This charge transfer causes an isostructural phase transition with volume contraction by 0.6% as well as semiconductor-to-metal and antiferromagnetism-to-paramagnetism transitions. Although the Bi cation at the A site does not take part in the charge transfer, it appears to enhance the charge-transfer temperature by stabilizing the square-planar coordinated Cu3+.