An endoscope adaptor to be connected to a robot arm of a robotic surgical system through a drape adaptor according to an embodiment may include a base section, a holding section, a driven member, and a transmission mechanism. The base is to be detachably connected to the drape adaptor. The driven member is rotatably provided on the base section and configured to be rotated by a rotation drive section of the robot arm through the drape adaptor. The holding section holds an endoscope rotatably about a rotation axis, the endoscope including an insertion section including an image capturing section provided at a distal end of the insertion section and a body section connected to the insertion section, wherein the rotation axis extends in a direction in which the insertion section extends. The transmission mechanism is configured to transmit rotation of the driven member to the holding section holding the endoscope.
