[Object] To detect airspeed and an airflow direction with respect to an airframe of a motorized aircraft with high accuracy without increasing the cost and weight and rapidly control attitudes of an electric propulsion system and the airframe in accordance with fluctuations of the airspeed and airflow direction. [Solving Means] An electric propulsion system control device includes: a first airspeed measurement unit that is mounted on an airframe of an aircraft and includes a first propulsion system parameter detector that detects a propulsion system parameter, the propulsion system parameter being a parameter of an electric propulsion system, the electric propulsion system being driven by an electric motor and rotating about a rotation axis as a center, and a first airspeed calculator that calculates first airspeed on a basis of the propulsion system parameter, the first airspeed being airspeed with respect to a first direction that is a direction of the rotation axis; a second airspeed measurement unit that is mounted on the airframe and measures second airspeed, the second airspeed being airspeed with respect to a second direction different from the first direction; and an airflow calculator that calculates airspeed and airflow direction with respect to the airframe on a basis of the first direction and the first airspeed and the second direction and the second airspeed.