In a voltage supply control device, a voltage conversion circuit receives a voltage from a battery and generates a desired voltage. A switching control unit executes switching so as to supply a voltage to a power amplification circuit through the voltage conversion circuit when the voltage of the battery is equal to or more than a predetermined threshold value or supply the voltage to the power amplification circuit from the battery without intervention of the voltage conversion circuit when the voltage of the battery is less than the predetermined threshold value. The switching control unit uses different voltage threshold values for a plurality of transmission modes classified in accordance with the assumed values of appropriate voltages to be supplied to the power amplification circuit. A cellular phone terminal and a voltage supply control method are also disclosed.