Abstract
In the present invention, the behavior of devices and the accessory devices of the devices is simulated. This apparatus comprises a first behavior calculation unit that calculates the behavior of a first object in a virtual space corresponding to a first device to which an accessory device is attached and a second behavior calculation unit that calculates the behavior of a second object in a virtual space corresponding to a second device. The second device includes an accessory device. At each predetermined time step, the first behavior calculation unit calculates, in the time step, the behavior of the first object corresponding to the first device to which the accessory device is attached, and then the second behavior calculation unit calculates the behavior of the accessory device attached to the first device on the basis of the calculated behavior of the first object.