PURPOSE: To change channel display and further to simplify the read of tuning data from a memory circuit in the tuning device in a frequency synthesizer system having the memory circuit for storing the tuning data.

CONSTITUTION: The tuning device in the frequency synthesizer system having a memory circuit 15 for storing the tuning data is provided with an area 15a storing the present station data of all the broadcasting channels in the memory circuit 15 in the case of presetting, an area 15b storing change data showing whether the channel display or fine control data are changed or not, and an area 15c storing the changed channel display or the fine control data. In the case of channel tuning, the present station data and the changed data are read out from the memory circuit 15 and when the change data is changed, the changed channel display or fine control data are successively read out of the memory circuit 15 so as to speedily tune and display the desired channel.