In an ATM switching control method, a table is formed to store the relationship between a memory address in a shared cell memory, at which an input cell is stored, and one of available area information indicating that the memory address in the shared cell memory is an available area and cell output information indicating that the memory address in the shared cell memory is an unavailable area. When a cell is to be input, available area information about the shared cell memory is used as a search key to search the table for a memory address in the shared cell memory. The input cell is stored in the shared cell memory in accordance with the searched memory address. Cell output information is stored in the table in accordance with the memory address in the shared cell memory at which the cell is stored. When the cell is to be read out, cell output information is used as a search key to search the table for a memory address in the shared cell memory. The cell is read out from the shared cell memory in accordance with the searched memory address. An ATM switch is also disclosed.