An endoscope plug member is an endoscope plug member that is installed in an opening portion of an endoscope having the opening portion which communicates with an outside, the endoscope plug member comprising: an opening portion side contact surface provided at the opening portion a plug body having a plug body side contact surface that blocks the opening portion by contacting the opening portion side contact surface attaching and holding means that holds the plug body movably in a direction in which the plug body side contact surface moves apart from the opening portion side contact surface, and is attachable to and detachable from the endoscope a plug body urging member that gives an urging force that presses the plug body in a direction in which the plug body side contact surface contacts the opening portion side contact surface to the plug body and a movable range adjusting portion that selectively changes a movable range of the plug body in the direction to move apart.