A pulse width modulation signal generation circuit and a pulse width modulation signal generation method are provided. A clock generator is configured for generating a clock signal including a plurality of pulses. The counting unit is coupled to the clock generator, and configured for storing a period parameter and outputting a counting value by counting the pulses of the clock signal based on the period parameter and a bidirectional counting mode. The comparing unit is coupled to the counting unit and is configured for comparing the counting value and a comparing threshold to output a level control signal. The signal generating unit is coupled to the comparing unit and configured for generating a pulse width modulation signal according to the level control signal. When the period parameter is odd, the counting value outputted by the counting unit is equal to a middle value in the two continuous clock cycles.