To provide a plastic working method and a plastic working system for smoothly feeding materials to be worked, and performing a high-speed operation by arraying a plurality of plastic working devices.

A plurality of press apparatuses 2 are arranged. Each press apparatus comprises a loop correction sensor 13 for monitoring the deflection of a coil material C intermittently fed from the preceding first press apparatus 2a and a second deflection monitoring means 19 for monitoring the deflection of the coil material C when feeding the coil to the succeeding second press apparatus 2b. The intermittent feed is converted into the continuous feed in a feed means 15 on the basis of the deflection caused by the intermittent feed of the coil material C from the first press apparatus 2a, acceleration/deceleration of the continuous feed rate is controlled, and the deflection of the coil material C when feeding the coil to the second press apparatus 2b is monitored by the second deflection monitoring means 19 to control the acceleration/deceleration of the preceding first press apparatus 2a.