Provided is a liquid supply device including: a plug having a plug side liquid channel; a socket having a socket side liquid channel; a hand configured to grip the socket and arrange the socket in a predetermined attitude at a three-dimensional position within the motion range; and an image capturing unit configured to recognize the orientation of the plug axis of the plug. The hand grips the socket so that the socket and the plug are in an attitude where the orientation of a socket axis matches the orientation of the plug axis recognized by the image capturing unit, and the socket gripped by the hand is inserted in the plug to couple the socket side liquid channel to the plug side liquid channel.