A biological detection device includes: a transmission unit transmitting a transmission wave into a compartment; a reception unit receiving a reflected wave; a creation unit creating three-dimensional map information on the compartment based on the reflected wave; a specifying unit specifying a position of a reflection source, which is an object having a reflection intensity equal to or greater than a predetermined value, in the three-dimensional map information when the vehicle where a person is seated is stopped; an object detection unit detecting a motion of an object in the compartment based on a Doppler shift of the reflected wave and outputting a detection result; and a person detection unit determining that there is no person at a position at which no person is detected in an immediately preceding detection cycle and which substantially matches the position of the reflection source.
BIOLOGICAL DETECTION DEVICE