A vehicle detector comprising a loop sensor, phase lock loop (PLL), frequency change detector, and a micro-processor including a logic circuit. Output of the PLL and the frequency change detector is inputted to the logic circuit, and the logic circuit performs logical OR operation of the output of the PLL and the output of the frequency change detector. The output of the logic circuit is used as a vehicle detection signal. The vehicle detector can detect vehicles at a low speed as well as vehicle at high speed accurately.