A novel non-intrusive technology for wrist pulse detection system has been developed and proposed for sleep monitoring using three types of radio frequency (RF) sensors. The three types of RF sensors for heart rate measurement on wrist, were the flexible RF single resonator, array resonators, and an injection-locked PLL resonator sensor. All three RF devices could detect heart rates at 0.2 to 1 mm distance from the skin of the wrist over clothes made of cotton fabric during sleep. Heart rates of 10 subjects were measured before and after sleep onset time using the device. The wrist pulse signals of a flexible RF single resonator were compared to the signals of a portable piezo-electric transducer as a reference. Then we confirmed that the heart rate after sleep onset time significantly decreased compared to before sleep. In conclusion, the RF system can be utilized as a non-contact non-intrusive method for measuring heart rates during sleep.