A majority voting processing device performs majority voting on respective bits of information data piece including r-number of bits (r is an integer of 2 or greater). The device includes a memory including a plurality of memory element groups each including r-number of memory elements that store data for the corresponding r-number of bits, respectively, the plurality of memory element groups each being provide for one address. A memory access unit writes each bit of the information data piece in k-number (k is an odd number of 3 or greater) of the memory elements in the memory element group corresponding to one address, and reads out the k-number of bits written in the k-number of the memory elements corresponding to that one address. A majority voter that performs majority voting on the k-number of bits read out from the memory by the memory access unit.