An abnormality detecting system configured to detect an abnormality of an actuator based on a travel time of a movable portion that is displaced between one end and another end of the actuator, the system comprising: the actuator; a first sensor that is configured to sense the movable portion when it has been displaced to the one end; a second sensor that is configured to sense the movable portion when it has been displaced to the another end; an external input unit that is configured to input a stroke of the movable portion; a travel time calculating unit that is configured to calculate the travel time based on results of sensing obtained by the first sensor and the second sensor; a travel distance calculating unit that is configured to calculate a total travel distance of the movable portion based on number of operations of the movable portion and the stroke; an abnormality detecting unit that is configured to detect an abnormality of at least the actuator based on the travel time and either the number of operations or the total travel distance; and a directional control valve that is configured to supply a pressurized fluid selectively to the one end or the another end based on a control signal for displacing the movable portion between the one end and the another end by the selective supply of the pressurized fluid to the one end or the another end; wherein the travel distance calculating unit is configured to calculate the total travel distance by multiplying the number of operations and the stroke together; characterized in that the external input unit being configured to input a time threshold of the travel time, and either a number-of-operations upper limit for the number of operations or a distance threshold of the total travel distance, and the abnormality detecting unit is configured to detect an abnormality of the directional control valve when the travel time is equal to or longer than the time threshold, and either when the number of operations is less than the number-of-operations upper limit or when the total travel distance is less than the distance threshold, and detect an abnormality of the actuator when the travel time is equal to or longer than the time threshold and the number of operations is equal to or larger than the number-of-operations upper limit and when the total travel distance is equal to or longer than the distance threshold. the actuator; a first sensor that is configured to sense the movable portion when it has been displaced to the one end; a second sensor that is configured to sense the movable portion when it has been displaced to the another end; an external input unit that is configured to input a stroke of the movable portion; a travel time calculating unit that is configured to calculate the travel time based on results of sensing obtained by the first sensor and the second sensor; a travel distance calculating unit that is configured to calculate a total travel distance of the movable portion based on number of operations of the movable portion and the stroke; an abnormality detecting unit that is configured to detect an abnormality of at least the actuator based on the travel time and either the number of operations or the total travel distance; and a directional control valve that is configured to supply a pressurized fluid selectively to the one end or the another end based on a control signal for displacing the movable portion between the one end and the another end by the selective supply of the pressurized fluid to the one end or the another end; wherein the travel distance calculating unit is configured to calculate the total travel distance by multiplying the number of operations and the stroke together; characterized in that the external input unit being configured to input a time threshold of the travel time, and either a number-of-operations upper limit for the number of operations or a distance threshold of the total travel distance, and the abnormality detecting unit is configured to detect an abnormality of the directional control valve when the travel time is equal to or longer than the time threshold, and either when the number of operations is less than the number-of-operations upper limit or when the total travel distance is less than the distance threshold, and detect an abnormality of the actuator when the travel time is equal to or longer than the time threshold and the number of operations is equal to or larger than the number-of-operations upper limit and when the total travel distance is equal to or longer than the distance threshold.