In a light emitting display device which is actively driven by TFTs, light emitting display pixels are driven efficiently. In a light emitting display panel 10, a large number of light emitting display pixels 10a are arranged in a matrix pattern and measuring pixels 10b are arranged forming a line along one dataline. A constant current is supplied from a constant current source 11 to the measuring pixels 10b, and the forward voltage VF of the EL element in the measuring pixel 10b is obtained by a voltage detecting terminal 12. The value of the drive voltage supplied to the light emitting display pixels 10a is controlled based on the forward voltage VF. Thus, a drive TFT (Tr2) constructing the light emitting display pixel 10a can drive an EL element E1 in the state where a drop voltage (VD) of the degree by which a constant current characteristic can be ensured is ensured, and a power loss generated in the drive TFT can be effectively restrained.