An elevator governor comprising: a sheave on which a rope moving in response to the movement of an ascending and descending body of an elevator is wound, and which changes the rotation speed in one direction in response to the ascent speed of the ascending and descending body and changes the rotation speed in the other direction in response to the descent speed of the ascending and descending body; a fly-weight which is provided on a side surface of the sheave and increases and decreases a moving quantity to a radial outer side of the sheave in response to an increase and decrease in the rotation speed of the sheave; and a detector (12,13) which performs overspeed detection of the sheave when the fly-weight has moved to the radial outer side by a predetermined quantity; characterized by: a stopper which is provided in the sheave and performs a rotational movement with respect to the sheave so as to be arranged to the radial outer side of the fly-weight in the case where the sheave rotates in a predetermined direction which is either of the two rotational directions, thereby preventing the fly-weight from moving to the radial outer side more than the predetermined quantity; rotational position detection means which detects a rotational position of the sheave; object detection means which is provided in proximity to the sheave and detects the stopper in the case where the stopper has approached the object detection means; and determination means which determines a position of the stopper with respect to the sheave on the basis of the rotational position of the sheave during the detection of the stopper by the object detection means, a sheave on which a rope moving in response to the movement of an ascending and descending body of an elevator is wound, and which changes the rotation speed in one direction in response to the ascent speed of the ascending and descending body and changes the rotation speed in the other direction in response to the descent speed of the ascending and descending body; a fly-weight which is provided on a side surface of the sheave and increases and decreases a moving quantity to a radial outer side of the sheave in response to an increase and decrease in the rotation speed of the sheave; and a detector (12,13) which performs overspeed detection of the sheave when the fly-weight has moved to the radial outer side by a predetermined quantity; characterized by: a stopper which is provided in the sheave and performs a rotational movement with respect to the sheave so as to be arranged to the radial outer side of the fly-weight in the case where the sheave rotates in a predetermined direction which is either of the two rotational directions, thereby preventing the fly-weight from moving to the radial outer side more than the predetermined quantity; rotational position detection means which detects a rotational position of the sheave; object detection means which is provided in proximity to the sheave and detects the stopper in the case where the stopper has approached the object detection means; and determination means which determines a position of the stopper with respect to the sheave on the basis of the rotational position of the sheave during the detection of the stopper by the object detection means, a stopper which is provided in the sheave and performs a rotational movement with respect to the sheave so as to be arranged to the radial outer side of the fly-weight in the case where the sheave rotates in a predetermined direction which is either of the two rotational directions, thereby preventing the fly-weight from moving to the radial outer side more than the predetermined quantity; rotational position detection means which detects a rotational position of the sheave; object detection means which is provided in proximity to the sheave and detects the stopper in the case where the stopper has approached the object detection means; and determination means which determines a position of the stopper with respect to the sheave on the basis of the rotational position of the sheave during the detection of the stopper by the object detection means,