A biological information detector is adapted to be attached to a users body, and includes a light-emitting part, a reflecting part, a light-receiving part and a processing unit. The light-emitting part is configured to emit light toward the users body. The reflecting part is disposed in a periphery of the light-emitting part to reflect at least a part of the light emitted by the light-emitting part toward the users body. The light-receiving part is configured to receive light reflected at the users body to produce a light reception signal. The processing unit is configured to process the light reception signal to produce biological information.
