A measuring device and a measuring method are provided. The measuring device (1) includes an oscillating circuit (11), a time average frequency-frequency lock loop (12), and a digital signal processing circuit. The oscillation circuit (11) includes an element to be measured and is configured to output a signal having an oscillation frequency correlated with an element value of the element to be measured. The time average frequency-frequency lock loop (12) is configured to receive the signal output by the oscillation circuit (11) and output a frequency control word correlated with the oscillation frequency. The digital signal processing circuit is configured to read the frequency control word output by the time average frequency-frequency lock loop (12) and obtain the element value of the element to be measured according to the read frequency control word. The measuring device (1) is easy to integrate, has small volume, low power consumption, and high reliability, and can achieve high-precision measurement.