To provide a mask auxiliary tool for smoothly performing respiration and a conversation by using an original mask of a type available on the market and covering both a mouth and a nose without impairing the mask function of preventing drying of the nose and the inflow of dust or pollen.

This mask auxiliary tool 1 comprises an almost cylindrical body 2, an outlet 3 existing in the body 2, positioned below a nostril at installing time and having an expiration valve 6 opening outside and an opening part 5 existing in the body 2 and positioned on the almost front of the nose at installing time. Since a space is generated between a gauze surface of the mask and the nose and the mouth by installing the mask auxiliary tool 1 having such constitution under the mask, a stifling state of the respiration and troublesomeness at conversation time and meal time caused by sticking of the mask to the nose and the mouth can be eliminated.