An operator identifying apparatus for identifying an operator that has operated an apparatus having an operation unit, said operator identifying apparatus comprising: a first oscillator configured to output a first identifying signal; a first electrode connected to said first oscillator and disposed so as to be able to transfer said first identifying signal to a first operator; a second oscillator configured to output a second identifying signal that has a signal characteristic different from said first identifying signal; a detector array including at least one detector configured to detect said first identifying signal and said second identifying signal; a second electrode configured to transfer said second identifying signal to a second operator during a first period where said first oscillator is outputting said first identifying signal and said second oscillator is outputting said second identifying signal; a third electrode, disposed on said operation unit, configured to transfer, during the first period, said first identifying signal to said detector array when said first operator touches said operation unit and said second identifying signal to said detector array when said second operator touches said operation unit, wherein the second electrode is configured to transfer, when the first operator and the second operator are in physical contact with each other and/or when the first operator and the second operator are in an electrically conductible condition through the third electrode while simultaneously touching the operation unit, said first identifying signal to said detector array during a second period where said first oscillator is outputting said first identifying signal but that is different from said first period; and, a controller connected to said detector array, wherein when said detector array detects said first identifying signal during said first period but does not detect said first identifying signal during said second period, said controller determines that said first operator has operated said operation unit, and when said detector array detects said first identifying signal during said second period, said controller determines that said first operator and said second operator are involved in said operation, the operator identifying apparatus further comprising a switch (17a, 17b) configured to electrically connect said third electrode to said detector array and said second oscillator to said second electrode during said first period, and configured to electrically connect said second electrode to said detector array and disconnect said second oscillator from said second electrode and said third electrode from said detector array during said second period. a first oscillator configured to output a first identifying signal; a first electrode connected to said first oscillator and disposed so as to be able to transfer said first identifying signal to a first operator; a second oscillator configured to output a second identifying signal that has a signal characteristic different from said first identifying signal; a detector array including at least one detector configured to detect said first identifying signal and said second identifying signal; a second electrode configured to transfer said second identifying signal to a second operator during a first period where said first oscillator is outputting said first identifying signal and said second oscillator is outputting said second identifying signal; a third electrode, disposed on said operation unit, configured to transfer, during the first period, said first identifying signal to said detector array when said first operator touches said operation unit and said second identifying signal to said detector array when said second operator touches said operation unit, wherein the second electrode is configured to transfer, when the first operator and the second operator are in physical contact with each other and/or when the first operator and the second operator are in an electrically conductible condition through the third electrode while simultaneously touching the operation unit, said first identifying signal to said detector array during a second period where said first oscillator is outputting said first identifying signal but that is different from said first period; and, a controller connected to said detector array, wherein when said detector array detects said first identifying signal during said first period but does not detect said first identifying signal during said second period, said controller determines that said first operator has operated said operation unit, and when said detector array detects said first identifying signal during said second period, said controller determines that said first operator and said second operator are involved in said operation, the operator identifying apparatus further comprising a switch (17a, 17b) configured to electrically connect said third electrode to said detector array and said second oscillator to said second electrode during said first period, and configured to electrically connect said second electrode to said detector array and disconnect said second oscillator from said second electrode and said third electrode from said detector array during said second period.