A connecting device for jewelry and accessory comprising a spring member made in manner that a metallic plate with an elasticity is bent to form a plate spring comprising a first plate spring section and a second plate spring section and a connecting device body including a base plate and a spring casing section placed on the base plate. The first plate spring section has one end equipped with a locking portion and a pushing handle, while the second plate spring section has one end equipped with a spring body side wall section rising to surround the pushing handle, the spring body side wall section having curved edges curved to lower so that both side surface portions thereof continuing with its central portion has one of an arc configuration and a tapered configuration. On the other hand, the spring casing section of the connecting device body has a hollow portion to accept the spring member and has one side wall curved to lower to form an arc or tapered configuration. The curved side wall has an entry to insert the spring member. In the entry, an engaging portion is provided to engage with the locking portion of the spring member due to the elasticity of the plate spring when the spring member is inserted into the spring casing section.