a bus switching structure and a computer using the same , wherein input / output slot connections are switched to a desired i / o bus so that loads are distributed evenly over the i / o buses . the bus switching structure includes a switching unit and switching controller . the switching unit is located interposingly between an i / o slot and a plurality of i / o buses . the switching unit either connects or disconnects the i / o slot to or from each of the i / o buses in accordance with a switching signal . the switching controller outputs the switching signal to cause the switching unit to connect the i / o slot to one of the i / o buses and to disconnect the i / o slot from any of the other i / o bus , thereby effecting connection switchover between the i / o slot and the i / o buses .