To provide a method for using memory of a signal delay device, where a signal delay buffer can be realized by using idle areas dotted in a memory space and number of components of an AV device or an audio device is decreased so as to reduce product cost.

A higher-order bit string of a reference register 110 is used for an index section 11, and a lower-order bit string is used for an offset section 112. Idle areas used for a signal delay buffer among idle areas dotted in a memory space are used for a memory block, and a start address table 120 is produced, which stores a start address of each memory block in cross- reference with a value indicated by the index section 111. Then the value of the reference register 110 is added, and a bit string outputted from the offset section 112 is added to the start address outputted from the start address table 120 to designate an address of a storage area to/from which data are given/ outputted.