A light emitting unit emits light including first light and second light. A light receiving unit outputs a signal of a level in accordance with intensity of incoming light. A first optical sensor is configured to outputs a first signal of a level in accordance with intensity of the first light entering the light receiving unit. A second optical sensor outputs a second signal of a level in accordance with intensity of the second light entering the light receiving unit. Based on the second signal, a controller determines whether or not the living body information sensor and a surface of the living body are in close contact with each other. The controller generates the information related to the living body based on the first signal obtained when the living body information sensor and the surface of the living body are in close contact with each other.
