A display apparatus that is capable of operating with power supplied from a battery, the display apparatus comprising: a display unit having a backlight as light source, the backlight comprising light emitting devices, detection means configured to detect whether or not a supply voltage from the battery is less than or equal to a threshold value; and drive means configured to supply a drive current to drive the light emitting devices included in the display unit, wherein the drive means includes current-changing means configured to change the drive current to be supplied to display unit from a first current (Ia) to a second current (Ib), which is lower than the first current, when the detection means detects that the supply voltage is less than or equal to the threshold value, characterized in that the current-changing means is arranged to change the current by means of a variable resistance unit configured to vary a resistance value in accordance with a detection result from the detection means; and wherein the current-changing means further comprises a current supply unit configured to supply the first or second drive currents (Ia, Ib) on the basis of the resistance value set by the variable resistance unit and wherein the drive means includes drive-time-period-changing means configured to change a duty cycle of the drive current specifying a time period for which the drive current is to be supplied to the display unit so that the light emitting devices are on so that the duty cycle becomes large when the detection means detects that the supply voltage is less than or equal to the threshold value, the drive-time-period-changing means being arranged so that when the current-changing means changes a drive current from the first drive current (Ia), denoted la, to the second drive current (Ib), denoted Ib, the drive-time-period-changing means changes from a first duty cycle denoted Da to a second duty cycle denoted Db so that the relationship of Ia/Ib = Db/Da is satisfied. a display unit having a backlight as light source, the backlight comprising light emitting devices, detection means configured to detect whether or not a supply voltage from the battery is less than or equal to a threshold value; and drive means configured to supply a drive current to drive the light emitting devices included in the display unit, wherein the drive means includes current-changing means configured to change the drive current to be supplied to display unit from a first current (Ia) to a second current (Ib), which is lower than the first current, when the detection means detects that the supply voltage is less than or equal to the threshold value, characterized in that the current-changing means is arranged to change the current by means of a variable resistance unit configured to vary a resistance value in accordance with a detection result from the detection means; and wherein the current-changing means further comprises a current supply unit configured to supply the first or second drive currents (Ia, Ib) on the basis of the resistance value set by the variable resistance unit and wherein the drive means includes drive-time-period-changing means configured to change a duty cycle of the drive current specifying a time period for which the drive current is to be supplied to the display unit so that the light emitting devices are on so that the duty cycle becomes large when the detection means detects that the supply voltage is less than or equal to the threshold value, the drive-time-period-changing means being arranged so that when the current-changing means changes a drive current from the first drive current (Ia), denoted la, to the second drive current (Ib), denoted Ib, the drive-time-period-changing means changes from a first duty cycle denoted Da to a second duty cycle denoted Db so that the relationship of Ia/Ib = Db/Da is satisfied.