VIBRATION DEVICE AND VIBRATION CONTROL METHOD

A vibration device according to the present invention includes a light transmissive body that transmits light of a predetermined wave length, a first cylindrical body that supports the light transmissive body at the one end, a plate-shaped spring portion that supports the other end of the first cylindrical body, a second cylindrical body that supports, at the one end, a position of the spring portion in an outer side portion of a position at which the first cylindrical body is supported, and a vibrating body that is arranged on the other end side of the second cylindrical body and vibrates in a penetrating direction of the second cylindrical body, in which the light transmissive body has a main body portion located on an inner side of a portion supported by the first cylindrical body, and a protruding portion extending from the main body portion toward an outer circumference of the light transmissive body and protruding outward more than a portion supported by the first cylindrical body, a ratio between an equivalent mass calculated from a moment of inertia of the protruding portion and a weight of the main body portion is equal to or more than 0.8 and equal to or less than 1.2, and the light transmissive body, the first cylindrical body, the spring portion, and the second cylindrical body are configured such that a resonant frequency of the light transmissive body is larger than a resonant frequency of the spring portion.