A wireless thermometer is provided, which measures a deep temperature with high accuracy and has an improved communication distance. A wireless thermometer includes a flat film-like substrate. A quartz crystal vibrator and an antenna are disposed on a principal surface of the substrate. A quartz crystal vibrator and an antenna are disposed on the other principal surface of the substrate. A winding conductor of the antenna is substantially symmetrical with a winding conductor of the antenna with respect to the substrate. A lead conductor of the antenna is connected to the winding conductor at one end and is connected to the quartz crystal vibrator at the other end. A central portion of the lead conductor is bent. By folding the central portion, the quartz crystal vibrator can be positioned opposite the quartz crystal vibrator with a heat insulator interposed there between.