POWER SUPPLY SYSTEM

In a non-contact power supply system, each of a main power supply device and a sub power supply device includes a timer counter. The main power supply device transmits a square wave to the sub power supply device. The sub power supply device performs interrupt processing when a value of the square wave transmitted from the main power supply device changes to compare a count value of the timer counter at that timing with a determination value, and when the count value is smaller than the determination value, makes a carrier cycle of the timer counter shorter than a predetermined cycle, and when the count value is greater than the determination value, makes the cycle of the timer counter longer than the predetermined cycle.