An independent and interlocking redundancy system includes one or more control targets, operation processors, and one or more standby processors. The one or more standby processors is configured to make transition from a standby state to a warming-up state when one of the operation processors malfunctions, transmit, in the warming-up state and to the one or more control targets, a control command same as that transmitted to the one or more control targets by non-malfunctioning one of the operation processors, at a timing at which the malfunctioning one of the operation processors is supposed to transmit the control command, and determine and transmit the control command independently from and by taking turns with respect to the non-malfunctioning one or more of the operation processors, after warm-up of the one or more standby processors is completed.