A biological information detecting device includes at least one light emitting section, a first light receiving section, a second light receiving section, and a processing section configured to acquire biological information on the basis of at least one a first detection signal acquired from the first light receiving section and a second detection signal acquired from the second light receiving section. The processing section switches an operation mode to one of a first operation mode for acquiring the biological information on the basis of the first detection signal and the second detection signal and a second operation mode for acquiring the biological information on the basis of one detection signal of the first detection signal and the second detection signal.