A semiconductor storage device comprises a memory block including first and second memory cells, first and second word lines electrically connected to the first and second memory cells, respectively, first and second booster circuits, and a control circuit. During a read operation in which the first word line is a selected word line, the control circuit controls the first booster circuit to start boosting the output voltage thereof before a target block address associated with the read command is determined, causes the output voltage of the first booster circuit to be supplied to the first and second word lines, controls the second booster circuit to start boosting the output voltage thereof, and causes the output voltage of the second booster circuit, instead of the output voltage of the first booster circuit, to be supplied to the first word line.