A computer includes a first memory, a second memory having an I/O speed lower than an I/O speed of the first memory, a storage device, and a processor. The first memory has a work area and a first cache area where data input to and output from the storage device is temporarily stored and the second memory has a second cache area where the data input to and output from the storage device is temporarily stored and a swap area to be a saving destination of data stored in the work area. The processor reduces the work area and expands the first cache area, when an input/output amount to be an amount of data input to and output from the storage device is larger than a predetermined input/output amount.