PURPOSE: To prevent accumulation and stopping of a developing agent in the vicinity of the outlet of a developing agent returning means, by installing a spiral coil spring and flexible guide member, whose side which is joined with a developing means is fixed to the coil spring inside the spring, to the developing agent returning means.

CONSTITUTION: A toner carrying section 92 is housed in a pipe 111 which communicates a toner receiving section 90 with a toner discharging section 91 and equipped with a plate-made spiral coil spring 112 which is a spiral member carrying toner (a) when it rotates and a closely-contacted type coil spring 112a which is provided inside the coil spring 112 and, at least, whose toner discharging side 91 which is the joining side of the coil spring 112a with a developing device is fixed to the coil spring 112 by brazing. The spring coil 112a is used as a flexible guide member. The coil spring 112a has the same length as the pipe 111 communicating the sections 90 and 91 with each other and is made to contact with both end sections of the pipe 111 inside the pipe 111 so that the spring 112a can be controlled by the pipe 111.