The invention relates to an engagement chain type driving device including a pair of driving sprockets, which rotate positively and reversely in opposite directions about a pair of rotating shafts, a pair of engagement chains, which engage with each other by the pair of driving sprockets so to be integrated together, and a driving source, which drives the pair of driving sprockets, wherein the engagement chain includes inner tooth plates and outer tooth plates, which each include buckling limiting flat surfaces, the inner tooth plates and outer tooth plates being brought opposite to each other and into contact with each other when the engagement chains are integrated by the pair of driving sprockets, such that the flat surfaces hold the chain engagement position.