Abstract: An operation input device includes an operation detection unit that detects an operation that has been made, the operation detection unit having a plurality of operation regions to which, of functions executed by a controlled device, a same type of functions are assigned, and a controller that determines one of the plurality of operation regions in which an operation has been detected by the operation detection unit to be a master operation region and the other of the operation regions to be a slave operation region, and outputs, to the controlled device, control information for controlling such that a state of the function assigned to the slave operation region is matched to a state of the function assigned to the master operation region