The objective of this paper is to clearly understand the characteristics of the voice picked up from the outer skin of a larynx (VOSL) with a throat microphone. This microphone is frequently employed in noisy environments to obtain the speech quality of high signal-to-noise ratio. It is known that VOSL lacks high frequency component comparing to the normal speech radiated from the lips. The transfer characteristics of the path from the glottis to the outer skin of a larynx is speculated from the long term spectrum. It is revealed that the relative amplitude between vowels of VOSL is different from that of the normal speech. Even if high frequency component of VOSL is emphasized, its characteristics do not completely get close to that of the normal speech. Furthermore, measurement of formant frequency on VOSL is discussed.