A sense amplifier for reading a via Read-Only Memory (Via-ROM) is provided. The sense amplifier includes a read circuit, an adaptive keeper circuit and a leakage monitor circuit. The read circuit is connected to the via-ROM. The adaptive keeper circuit is connected to the read circuit. The leakage monitor circuit is connected to the adaptive keeper circuit for forming a current mirror, such that the adaptive keeper circuit compensates a read voltage of a memory cell whose via is opened when a bit-line leakage is happened.