A wireless terminal includes a pressure sensor, a wireless circuit, and a case accommodating the pressure sensor and the wireless circuit in a waterproof manner, and is left inside a stomach of a livestock animal to measure pressure inside the stomach and wirelessly transmit acquired pressure data. The case includes a cylindrical case body and a lid member closing an opening of the case body. The lid member has a measurement hole extending between inside and outside of the lid member and a protection wall part located outside of the case body. The measurement hole has a pressure-receiving pressure measurement part inside for measurement of the pressure and is closed. The measurement hole includes a first linear part and a second linear part intersecting in T shape with the first linear part, and has distal ends open to an outer face of the protection wall part.