A control device of an embodiment includes an airbag inflated at least onto a hood of a vehicle by being filled with gas supplied from a gas supply, a recognizer that recognizes a surroundings situation of the vehicle, an index value deriver that derives an index value indicating a degree of overlap in a vehicle width direction between a traffic participant recognized by the recognizer and the vehicle when the traffic participant comes into contact with the vehicle, and an airbag controller that controls a timing at which the airbag is inflated, on the basis of the index value derived by the index value deriver.