To provide an image forming apparatus which reduces costs and realizes consumption power reduction when executing a monochrome mode (a second mode).

An image forming apparatus executes one of a plurality of modes including a first mode and a second mode. The first mode forms an image on a recording material using each image forming part Y, M, C, Bk. The second mode forms an image on a recording material only using the image forming part Bk without the image forming parts Y, M, C. When the second mode is executed, a DC voltage power supply 22a applies a DC voltage on a charging roller 2d provided on the image forming part Bk. In addition, an AC voltage power supply 21 stops an application of an AC voltage on charging rollers 2a-2d respectively provided on the image forming parts Y, M, C, Bk, and a DC voltage power supply 22b stops an application of a DC voltage on the charging rollers 2a-2c provided on the image forming parts Y, M, C.