PURPOSE: To specify the storage address of a sin(x) or cos(x) corresponding to an input value (x) by specifying the sin(x) or cos(x) according to a function indication and controlling an address θ corresponding to the (x).

CONSTITUTION: The input (x) is inputted to an input register 1, and converted into an address by a converting means 2. A mode specifying circuit specifies a sin mode. When a table in a sin terms is present in a memory 6, an address control circuit 4 transmits the address converted by the converting means 2 to an address register 5 as it is, and the corresponding address θδC is outputted. The mode specifying circuit 3 specifies a cos mode. When the memory 6 is of a sin table, the address control circuit 4 transmits the address corresponding to θ+π/2 to the address register 5, and the corresponding address θC is read out of the memory 6. Thus spaces required for sin (x) and cos (x) function generators are unnecessary, and moreover it is unnecessary to convert the (x) for inputting.