Abstract: A portable device, and related method, that allows the values of one or more parameters characterising the operation of a mechanical watch to be measured. The device is provided with a contact microphone including a contact piece and a piezoelectric element. The contact piece is brought into physical contact with the case of a watch during a measurement period. The device further includes a power source, such as a rechargeable or replaceable battery, a microprocessor, a memory, and a screen for displaying the values measured, preferably a touch-sensitive screen. Preferably, the dimensions of the device are of a same order of magnitude as the case of a wristwatch. The device may have the shape of a horological eyeglass.