An anomaly determination device for use with a turbocharger, wherein the turbocharger includes a turbine housing, which includes a scroll passage, in which a turbine wheel configured to be rotated by exhaust gas is housed, a discharge passage, which is connected to the scroll passage and in which exhaust gas from the scroll passage flows, and a bypass passage, which connects a section of the scroll passage upstream of the turbine wheel to the discharge passage, a wastegate, which abuts against a valve seat provided in the turbine housing when the bypass passage is fully closed; an electric actuator configured to drive the wastegate; a coupling mechanism, which couples the wastegate to the actuator; a stopper, which abuts against the wastegate or the coupling mechanism when the bypass passage is fully open to restrict a movement of the wastegate to an open position; a sensor, which detects a position of an output shaft of the actuator; a control unit, which controls energization of the actuator; and an anomaly determination unit, which determines whether an anomaly is present in the coupling mechanism based on a detection value detected by the sensor, the anomaly determination unit is configured to execute a first anomaly determination process for determining that an anomaly is present in the coupling mechanism when at least one of two conditions is met, the conditions being a condition that a fully-closed-time detection value is outside a closed-side normal range set in advance and a condition that a fully-open-time detection value is outside an open-side normal range set in advance, and a second anomaly determination process for determining that an anomaly is present in the coupling mechanism if a difference between the fully-closed-time detection value and the fully-open-time detection value is outside a normal distance range set in advance when it is not determined in the first anomaly determination process that an anomaly is present in the coupling mechanism and at least one of two conditions is met, the conditions being a condition that the fully-closed-time detection value is a value between a first threshold set in the closed-side normal range and a closed-side boundary value of the closed-side normal range and a condition that the fully-open-time detection value is a value between a second threshold set in the open-side normal range and an open-side boundary value of the open-side normal range, the anomaly determination unit is further configured to determine that no anomaly is present in the coupling mechanism without executing the second anomaly determination process when two conditions are met that are a condition that the fully-closed-time detection value is a value between the first threshold and an open-side boundary value of the closed-side normal range and a condition that the fully-open-time detection value is a value between the second threshold and a closed-side boundary value of the open-side normal range, the fully-closed-time detection value is a detection value of the sensor when the control unit energizes the actuator to cause the wastegate to abut against the valve seat, and the fully-open-time detection value is a detection value of the sensor when the control unit energizes the actuator to cause the wastegate to abut against the stopper. a scroll passage, in which a turbine wheel configured to be rotated by exhaust gas is housed, a discharge passage, which is connected to the scroll passage and in which exhaust gas from the scroll passage flows, and a bypass passage, which connects a section of the scroll passage upstream of the turbine wheel to the discharge passage, a first anomaly determination process for determining that an anomaly is present in the coupling mechanism when at least one of two conditions is met, the conditions being a condition that a fully-closed-time detection value is outside a closed-side normal range set in advance and a condition that a fully-open-time detection value is outside an open-side normal range set in advance, and a second anomaly determination process for determining that an anomaly is present in the coupling mechanism if a difference between the fully-closed-time detection value and the fully-open-time detection value is outside a normal distance range set in advance when it is not determined in the first anomaly determination process that an anomaly is present in the coupling mechanism and at least one of two conditions is met, the conditions being a condition that the fully-closed-time detection value is a value between a first threshold set in the closed-side normal range and a closed-side boundary value of the closed-side normal range and a condition that the fully-open-time detection value is a value between a second threshold set in the open-side normal range and an open-side boundary value of the open-side normal range,