Problem to be solved: to provide a hearing aid, a sound collecting device and a volume measuring system capable of measuring the noise conditions in the external auditory canal while protecting the ear from the noise for the purpose of preventing the noise deafness.Solution: an ear plug comprising a tubular member capable of extending in one direction and curved to the one direction, a first acoustic sensor that is collected through the tubular member, and an earplug type sound insulation member through which the tubular member is inserted.The tubular member is preferably curved along the shape of the external auditory canal.It is preferred that the first acoustic sensor is provided in the enclosure, and is collected through the tubular member and the first opening.Diagram【課題】騒音性難聴の予防を目的として、騒音から耳を保護しながら外耳道内の騒音状況を測定することが可能な耳栓、集音装置、及び、音量測定システムを提供する。【解決手段】一方向に伸延し、前記一方向に対して湾曲可能な管状部材と、前記管状部材を介して集音する第１音響センサと、前記管状部材が挿通される耳栓型の遮音部材とを含む、耳栓。前記管状部材は、外耳道の形状に沿って湾曲可能であることが好ましい。前記管状部材に連通した第１開口部を有する筐体を含み、前記第１音響センサは、前記筐体内に設けられ、前記管状部材及び前記第１開口部を介して集音することが好ましい。【選択図】図２
