In this paper, we have designed a microwave level meter based on the FM-CW radar theory using a YIG-tuned oscillator (YTO). YTO has an excellent frequency linearity, so a linearizer circuit is not necessary for the level meter. It is shown that interference signals reflected from nearby obstacles can be removed by using a digital band-pass filter. An FIR band-pass filter is designed using the Kaiser window. The distance measurement has been performed in the outdoor test field. The measurement data have been obtained for the range of 1~40m with 1m step, and the results show that the standard deviation of the measured data is 2.33 cm. The level meter manufactured in this study can be applied usefully in the industrial facilities which are not accessible easily, for example, to measure the level of molten metal in the iron and steel company.