An automatic tuning apparatus, such as an automatic channel selector as incorporated in a television receiver, comprising a tuner using a voltage controlled variable capacitance diode such that the variable capacitance thereof constitutes a portion of a tuning circuit of the tuner for changing the tuning frequency thereof, and a solid state electrochemical potential memory device, an output voltage of which is applied to the capacitance diode in a reverse direction, which memory device is controlled so as to be charged or discharged in response to selective manual operation until an increased or decreased terminal voltage thereof decreases or increases, respectively the capacitance across the diode and thus increases or decreases, respectively the tuning frequency of the tuner and a particular frequency is tuned. An intermediate frequency output, obtained as a result of tuning, is used to disable the abovementioned charging or discharging operation of the potential memory device.