The invention provides an electrophotographic toner, an electrophotographic developing agent, apparatus and device of using the same. The lectrophotographic toner includes a binder resin and a colorant, wherein, with a total intensity (kcps) of all elements detected in the toner due to fluorescent X-ray measurement designated as A and an intensity of nitrogen designated as B, B/A is from about 0.01 to about 0.5, and a ratio of nitrogen measured by X-ray photoelectron spectrometry after ion etching at an accelerating voltage of 10 mV for 180 seconds is from about 0.1 atom % to about 7.5 atom %.