An image forming apparatus, comprising: a plurality of photosensitive bodies (41Y,41M,41C,41K) having transfer points to transfer images onto a transfer object; a driving source (110,120,130,140) to drive at least two photosensitive bodies of the plurality of photosensitive bodies; characterized in that the apparatus further comprises: a driving gear train (200,300,400,500) arranged between the driving source and the photosensitive bodies provided to transmit driving power from the driving source to the at least two photosensitive bodies, the driving gear train including photosensitive body shaft gears (220Y,220M,220C,220K; 320Y,320M,420C,420K;520Y,520M) respectively connected to the photosensitive bodies, wherein the driving source drives connecting gears (230,240,250,260,270;330a,430a; 530a,540,550a,560a,570) arranged so as to transmit the driving power to the photosensitive body shaft gears and provide reduction in speed between the driving source and the photosensitive body shaft gears, wherein when one of the photosensitive body shaft gears is set to a reference photosensitive body shaft gear, the number of teeth of the connecting gear, which is disposed at a j th position from the reference photosensitive body shaft gear, is determined so that a value calculated from the following equation is substantially an integer: L πD ⋅ 1 R j here, D refers to a diameter of each of the photosensitive bodies, L refers to a distance between the transfer points of two adjacent photosensitive bodies, and R j refers to a speed reduction ratio from the j th connecting gear to the reference photosensitive body shaft gear. a plurality of photosensitive bodies (41Y,41M,41C,41K) having transfer points to transfer images onto a transfer object; a driving source (110,120,130,140) to drive at least two photosensitive bodies of the plurality of photosensitive bodies; characterized in that the apparatus further comprises: a driving gear train (200,300,400,500) arranged between the driving source and the photosensitive bodies provided to transmit driving power from the driving source to the at least two photosensitive bodies, the driving gear train including photosensitive body shaft gears (220Y,220M,220C,220K; 320Y,320M,420C,420K;520Y,520M) respectively connected to the photosensitive bodies, wherein the driving source drives connecting gears (230,240,250,260,270;330a,430a; 530a,540,550a,560a,570) arranged so as to transmit the driving power to the photosensitive body shaft gears and provide reduction in speed between the driving source and the photosensitive body shaft gears, wherein when one of the photosensitive body shaft gears is set to a reference photosensitive body shaft gear, the number of teeth of the connecting gear, which is disposed at a j th position from the reference photosensitive body shaft gear, is determined so that a value calculated from the following equation is substantially an integer: L πD ⋅ 1 R j here, D refers to a diameter of each of the photosensitive bodies, L refers to a distance between the transfer points of two adjacent photosensitive bodies, and R j refers to a speed reduction ratio from the j th connecting gear to the reference photosensitive body shaft gear. a driving gear train (200,300,400,500) arranged between the driving source and the photosensitive bodies provided to transmit driving power from the driving source to the at least two photosensitive bodies, the driving gear train including photosensitive body shaft gears (220Y,220M,220C,220K; 320Y,320M,420C,420K;520Y,520M) respectively connected to the photosensitive bodies, wherein the driving source drives connecting gears (230,240,250,260,270;330a,430a; 530a,540,550a,560a,570) arranged so as to transmit the driving power to the photosensitive body shaft gears and provide reduction in speed between the driving source and the photosensitive body shaft gears, wherein when one of the photosensitive body shaft gears is set to a reference photosensitive body shaft gear, the number of teeth of the connecting gear, which is disposed at a j th position from the reference photosensitive body shaft gear, is determined so that a value calculated from the following equation is substantially an integer: L πD ⋅ 1 R j