This invention relates to a cleanerless developing method using a mono-component toner, which method effects simultaneous developing and cleaning operations in the step of development. It more particularly relates to a method which is capable of forming images of outstanding quality without entailing generation of positive memory or negative memory. In the cleanerless developing method using a mono-component toner, the absolute value of the magnitude, .vertline.q.sub.t .vertline., of charging the developing toner to be used is selected to fall in the range between 0.5 [mC/kg] and 40 [mC/kg], the absolute value of the magnitude, .vertline.q.sub.r .vertline., of charging the residual toner to be introduced into the step for simultaneous developing and cleaning as deposited on the surface of the latent image retaining member is set to fall in the range between 0.5 [mC/kg] and 60 [mC/kg], or the absolute value of the magnitude, .vertline.q.sub.z .vertline., of charging the residual toner during the step for uniformizing the residual toner is selected to fall below the upper limit of 40 [mC/kg]. By selecting the magnitude of charging the toner within at least one of the ranges mentioned above, the cleanerless developing method using a mono-component toner is always and easily enabled to produce images of high quality without entailing the generation of positive memory or negative memory.