A contact state estimating device includes: a first and a second electrode brought into contact with an object to be measured； a direct current voltage supply unit； a signal switching unit configured to switch a first pathway through which the direct current voltage supply unit supplies direct current voltage to the first electrode and an output signal from the second electrode is output and a second pathway through which the direct current voltage supply unit supplies direct current voltage to the second electrode and an output signal from the first electrode is output to each other； and a contact state estimating unit configured to estimate a contact state of the first electrode or the second electrode with the object , based on the output signal acquired at a timing at which a pulse noise is anticipated to occur in association with switching between the first pathway and the second pathway.
