A living body information detection apparatus including a pair of arms opposed to each other. The apparatus including a spindle for connecting between the arms of the pair at each end of the arms. The apparatus further including a distance variable mechanism, provided in the spindle, for adjusting an interval between the other ends of the pair of arms. The apparatus also including a detection part, for detecting living body information, attached to the other end of at least one arm of the pair of arms on a side opposed to another arm. The detection part is arranged on the top end of an adjusting screw which is installed in the other screw hole penetrating the arms.