An electrophotographic image forming device includes an image forming unit to apply a developer to a paper and to form an image thereon. The electrophotographic image forming device further includes a fusing unit having a fusing roller to receive the paper from the image forming unit, to fix the developer on the paper, and to move the paper, and a housing containing the image forming unit, and having a fusing unit accommodating part to detachably receive the fusing unit along a direction that is different than a paper transfer direction to be accommodated therein. Thus, the electrophotographic image forming device allows the fusing unit to be detachably mounted therein safely and conveniently.