A biological information detection device includes first and second light sources, an image capturing system, and an arithmetic circuit. The first and second light sources project, onto a living body, at least one first dot formed by first light and at least one second dot formed by second light, respectively. The image capturing system includes first photodetector cells and second photodetector cells. The image capturing system generates and outputs a first image signal and a second image signal. The arithmetic circuit generates information concerning the living body, by using the first and second image signals. The first light includes fifth light. The second light includes sixth light. Each of the fifth light and the sixth light has a wavelength in a range from 650 nm to 950 nm. The wavelength of the sixth light is longer than that of the fifth light by 50 nm or more.
