A control device includes: a dummy memory cell group; a transistor having a first terminal, a grounded second terminal and a control terminal; an adjustor providing a resistance between the dummy memory cell group and the first terminal of the transistor; an inverter generating, based on a voltage at the first terminal of the transistor, a sense start signal that is associated with switching of a sense amplifier circuit of a semiconductor memory device from a disabled state to an enabled state; and a controller generating, based on the sense start signal, a control signal for controlling the transistor such that switching of the transistor from conduction into non-conduction is associated with the sense start signal.