An automatic analyzer uses probes for detecting liquid levels based on a capacitance detection method. Erroneous detection of liquid levels due to interference caused by the frequency difference of oscillators is reducted. When frequencies f1 and f2 of respective detector ocillators, which are originally equal to each other, are different by approximately several Hz from each other due to a manufacturing variation, oscillation waveforms are added to liquid level detection voltages, causing a premature determination that the probes have contacted the liquid surface before actual contact therewith. By setting the difference between the frequencies f1 and f2 of the detector oscillators to be in the range of several kHz, an oscillation waveform corresponding to the difference between the frequencies is added to the detection voltages, but the amplitude values of the high-frequency components are attenuated by high-frequency attenuators, thereby ensuring accuracy in the liquid level detection.