VIBRATION SENSOR AND EXTERNAL ENVIRONMENT DETECTION APPARATUS

PROBLEM TO BE SOLVED: To provide an easy-to-use vibration sensor detecting an external vibration by utilizing an electret.SOLUTION: A vibration sensor outputs a detection signal of an external vibration when a relative position between an electret group and an electrode group changes in accordance with a relative positional change between a first substrate and a second substrate due to the external vibration. The electrode group is divided into one or more prescribed number of phases, and a small electrode group capable of generating an electric signal corresponding to the external vibration is formed for each phase. The electrode group is provided with a phase difference generation interval according to the prescribed number of phases, the interval causing a prescribed phase difference between the electric signals generated in the plurality of small electrode groups between the adjacent electrodes included in the electrode group. When the relative position between the first substrate and the second substrate has changed due to the external vibration, the sensor outputs a signal formed by superimposing the electric signals generated by the plurality of small electrode groups as a detection signal of the external vibration.