A silent chain is provided, which can avoid impinging contact between guide plates and sprocket teeth and prevent wear loss and noise. A guide plate includes a main guide part formed on a side that engages with a sprocket, and an additional guide part formed on at least one of front and rear edges in the longitudinal direction of the chain. The additional guide part protrudes more in the longitudinal direction of the chain than an outer flank of a middle plate arranged in the same guide row and has a size that allows the additional guide part to overlap a sprocket tooth in the chain width direction when engaged with the sprocket S.