An image forming apparatus (10, 13), comprising: a housing; a plurality of photoconductors (32M, 32C, 32Y, 32Bk) on which an electrostatic latent image is formed, the photoconductors (32M, 32C, 32Y, 32Bk) being supported by a supporting shaft; a plurality of developing devices (31M, 31C, 31Y, 31Bk), each including at least a developing agent chamber configured to include a developing agent and a developing agent carrier (36M, 36C, 36Y, 36Bk) configured to hold the developing agent thereon; a transfer device comprising a belt member and rollers (51, 52), the transfer device being configured to transfer a visible image formed on the photoconductors (32M, 32C, 32Y, 32Bk) to a recording medium; a first holder configured to hold the plurality of photoconductors (32M, 32C, 32Y, 32Bk) and the plurality of the developing devices (31M, 31C, 31Y, 31Bk) along a first direction perpendicular to the supporting shafts of the photoconductors (32M, 32C, 32Y, 32Bk), the first holder being placed in a first area in the housing; a first guide configured to guide the first holder in and out of the first area in the first direction; and an image reader, provided at a top portion of the housing, configured to read an image on a document, characterized by a second holder configured to hold at least the belt member and the rollers (51, 52) for supporting the belt member, the second holder being placed in a second area in the housing; and a second guide configured to guide the second holder in and out of the second area in a second direction parallel to the first direction; wherein the first holder and the second holder are configured to be guided in and out of the first area and second area independently by the first guide and the second guide, respectively. a housing; a plurality of photoconductors (32M, 32C, 32Y, 32Bk) on which an electrostatic latent image is formed, the photoconductors (32M, 32C, 32Y, 32Bk) being supported by a supporting shaft; a plurality of developing devices (31M, 31C, 31Y, 31Bk), each including at least a developing agent chamber configured to include a developing agent and a developing agent carrier (36M, 36C, 36Y, 36Bk) configured to hold the developing agent thereon; a transfer device comprising a belt member and rollers (51, 52), the transfer device being configured to transfer a visible image formed on the photoconductors (32M, 32C, 32Y, 32Bk) to a recording medium; a first holder configured to hold the plurality of photoconductors (32M, 32C, 32Y, 32Bk) and the plurality of the developing devices (31M, 31C, 31Y, 31Bk) along a first direction perpendicular to the supporting shafts of the photoconductors (32M, 32C, 32Y, 32Bk), the first holder being placed in a first area in the housing; a first guide configured to guide the first holder in and out of the first area in the first direction; and an image reader, provided at a top portion of the housing, configured to read an image on a document, characterized by a second holder configured to hold at least the belt member and the rollers (51, 52) for supporting the belt member, the second holder being placed in a second area in the housing; and a second guide configured to guide the second holder in and out of the second area in a second direction parallel to the first direction; wherein the first holder and the second holder are configured to be guided in and out of the first area and second area independently by the first guide and the second guide, respectively.