An electrical connection box includes a terminal supporting wall that has a rescue terminal portion of a bus bar arranged on the front surface and is provided as a single piece with a block main body, and a cover member that exposes and covers the terminal supporting wall and the rescue terminal portion. Bearing holes are provided in the terminal supporting wall on one end side in the left-right direction, rotation support shaft portions that are rotatably fitted into the bearing holes are provided as protrusions on the cover member, the rescue terminal portion is exposed by rotating the cover member from an opening/closing end on the other end side in the left-right direction with the rotation support shaft portions serving as fulcrums, and ribs for holding the cover member in an isolating state are provided as protrusions on the opening/closing end side of the cover member and are semi-locked into latching depressions provided on the terminal supporting wall.