A control program for an automatic gain control device, characterized by causing control means of an automatic gain control device including an amplifier for an reception signal, which can set a gain, information processing means for extracting control data from an output from the amplifier and perfoming information processing for the data, storage means for storing a gain setting value of the amplifier, and control means for controlling a gain of the amplifier in accordance with a preset control algorithm,
- to control the gain of the amplifier in correspondence with operation of switching a frequency of a reception signal, which is accompanied by different frequency monitoring in a compressed mode by the information processing means, on the basis of a result obtain when the control means computes the gain setting value stored in the storage means in accordance with the present algorithm,
- wherein the present algorithm comprises an algorithm for predicting an optimal value of a gain value for a first reception signal after different frequency monitoring on the basis of an amount of change in gain setting value of the first reception siganl before different frequency monitoring and an amount of change in gain setting value for a second reception signal during different frequency monitoring.