The anomalous increase of Kerr effect due to pretransitional fluctuations has been investigated in the SmA phase close to the SntA-SmCalpha* transition point in antiferroelectric liquid crystals MHPOBC and MHPOCBC. We have developed a Landau theory taking into account the fluctuations and shown that there are two contributions to the Kerr effect. On the basis of theoretical results. the experimental results obtained in MHPOBC and MHPOCBC were discussed and a clear evidence of the fluctuation-induced Kerr effect was presented.