We propose a method to capture 3D video of an object that moves in a large area using active cameras. Our main ideas are to partition a desired target area into hexagonal cells, and to control active cameras based on these cells. Accurate camera calibration and continuous capture of the object with at least one third of the cameras are guaranteed regardless of the object's motion. We show advantages of our method over an existing capture method using fixed cameras. We also show that our method can be applied to a real studio. © 2010 Information Processing Society of Japan.