There are provided a device which can measure a reaction performance of a neurotransmission system and that of a muscle expansion/contraction system in a specific body part easily, and gives a direction that a muscle in a specific body part is to be in an unreacted state by muscle unreacted state directing means, gives a direction that the muscle in the part is to be shifted into a reacted state by muscle reacted state directing means, continuously measures impedance and time until the reaction of the muscle in the part is completed after it has been directed that the muscle in the part is to be in the reacted state by impedance measuring means and timing means, and computes the reaction time of a neurotransmission system and the reaction time of a muscle expansion/contraction system based on these continuously measured impedance and time by individual system reaction time computing means.