A display driver circuit for driving a current-controlled light-emitting device to emit light with a luminance gradation includes a memory for storing compensation data based on a measured value of a threshold voltage of a transistor for driving the light-emitting device, a register for holding the data to be displayed, and a data line driver for measuring the threshold voltage of the transistor through a data line connected to the transistor to produce the compensation data and store the compensation data in the memory and correcting the data to be displayed held in the register with the compensation data stored in the memory to output the gradation signal to the data line. Thus, the display driver circuit can be smaller in size than conventional circuitry which has a separate analog-to-digital converter.