An automatic door sensor includes: at least one sensor module unit (sensor module 11) configured to detect optically an object or a human body and to output, according to the detection results, a signal to a door controller for controlling an automatic door to open/close; an accommodation unit (profile 12) capable of accommodating the at least one sensor module unit; a cover member (front cover 13) that is transmissive to light for use for the detection performed by the sensor module unit and configured to cover the accommodation unit in which the sensor module unit is accommodated; and a functionality expansion module (LED module 14) either side of which can be joined to the cover member and that is configured to expand functionalities of the automatic door sensor by performing communication with the sensor module unit.