PROBLEM TO BE SOLVED: To provide a chewing detection device that can be worn for a long time and can accurately detect a mastication action (chewing).SOLUTION: A chewing detection device includes: earphone type external auditory canal sensors 11 and 12 having a set of a light emitting element 34 and a light receiving element 35 in which the light receiving element 35 receives the reflected light of the light that the light emitting element 34 emits to the inside of the external auditory canal, and outputs a voltage signal according to an amount of the received light； association processing means 51 for associating an output signal of the external auditory canal sensors 11 and 12 with a jaw action, and outputting a chewing signal to the effect that the jaw has performed chewing； and chewing section detection means 52 for determining whether or not the output of the external auditory canal sensors 11 and 12 is based on the jaw action (within a chewing section), and, when the output is not based on the jaw action (outside the chewing section), nullifying the output of the association processing means 51.SELECTED DRAWING: Figure 4【課題】長時間の装着が可能で、かつ、正確に咀嚼動作（チューイング）を検出できるチューイング検出装置を提供する。【解決手段】発光素子３４および受光素子３５の組を有し、発光素子３４が外耳道内へ発した光の反射光を受光素子３５が受光して、受光量に応じた電圧信号を出力するイヤホン型外耳道センサー１１，１２と、外耳道センサー１１，１２の出力信号を顎の動作と関連付け、顎がチューイングを行った旨のチューイング信号を出力する関連付処理手段５１と、外耳道センサー１１，１２の出力が顎の動作に基づくもの（チューイング区間内）か否かを判別して、顎の動作に基づかないとき（チューイング区間外）の関連付処理手段５１の出力を無効化するチューイング区間検知手段５２とを含むチューイング検出装置である。【選択図】図４
