A semiconductor device capable of enlarging a read margin of a memory cell and a method of surrounding a read of a memory are provided. The reference word line RWL is activated in a time division manner with respect to the plurality of word lines WL. The precharge circuit PRE applies the read potential VRD to the bit line BL, and the precharge circuit PRE flows the read current Icel from the selected memory cell MC and the read reference current Iref from the reference cell RC to the bit line BL in a time division manner. A detection currents Ird2a, Irr2a, each of which is a current proportional to the current flowing through the bitline BL, flows through the current detection line CDL.