An apparatus and method for fetal heart rate detection are disclosed, in which the method comprises the steps of: moving a stethoscope to a position close to a fetus for detecting an analog fetal heart tone signal； performing an analog-to-digital conversion operation upon the analog fetal heart tone signal； band-pass filtering the digital fetal heart tone signal for enabling the frequency of the resulting outputted digital fetal heart tone signal to fall in a specific frequency range； analyzing the waveform of the outputted digital fetal heart tone signal to determining whether the outputted digital fetal heart tone signal includes a first heart tone signal； analyzing the outputted digital fetal heart tone signal to determining whether its rate of the heart beat, i.e. the amount of heart beats per minutes, is falling in a specific range； reducing the high-pass frequency as well as the low-pass frequency respectively from the maximal and the minimal in the specific frequency range in a stepwise manner for maximizing the peak signal intensity of the first heart tone signal and also the signal to noise ratio (SNR) thereof； using a displacement sensor to register the current detection position of the stethoscope while moving the stethoscope to another position for another fetal heart tone signal collection； comparing the peak signal intensities and the signal to noise ratios of different first heart tone signal collected from different detection positions by the stethoscope for locating an optimal detection position corresponding one of those first heart tone signal with the maximum peak signal intensity and the signal to noise ratio； analyzing and obtaining a time difference between the peaks of the first heart tone signals that are collected immediately prior and after the optimal detection position while using the time difference to calculate a rate of heart beat； monitoring the first heart tone signal for evaluating whether its signal intensity and SNR are decreased
