To provide an inexpensive and reliable duplex information processor without increasing the information quantity of a signal to be shared between plural MCU even in the case of an outside input whose information quality is large.

This duplex information processor 10 is provided with two signal processing means 10A and 10B constituted of an MCU and a signal collating part 110 for collating two signal outputs S3A and S3B. A detection signal S1 of a sensor device S constituted of plural signal sensors is introduced to signal input terminals 11A and 11B of each signal processing means 10A and 10B. Also, logical signal sharing paths 30A and 30B are connected with each shared output terminal 31A and 31B. Each signal processing means 10A and 10B are provided with logical arithmetic parts 20A and 20B constituted of temporary logical arithmetic parts 70A and 70B and true logical arithmetic parts 80A and 80B. The temporary logical arithmetic operation and the true logical arithmetic operation are combined so that one integral signal processing in the logical arithmetic parts 20A and 20B can be constituted.