A control device includes a current detecting section that detects a sense current for a current flowing through a semiconductor element; a transient sensing period detecting section that detects a transient sensing period from a transient rising to a transient falling of a detection signal of the sense current, in response to the semiconductor element being turned ON; and a control section that controls the semiconductor element according to a detection result of the transient sensing period, based on the sense current detection signal. By detecting the transient sensing period with the transient sensing period detecting section and controlling the semiconductor element with the control section according to the transient sensing period detection result, based on the sense current detection signal, it is possible to identify overcurrent according to the transient response detection result of the sense current during the transient sensing period, and to actively protect the semiconductor element.