A charging device includes a charger and a power supply circuit. The charger is disposed opposing a latent image bearer. The power supply circuit applies to the charger an alternating voltage obtained by superimposing a pulsating voltage on a direct-current voltage. The alternating voltage generates normal discharge from the charger to a surface of the latent image bearer and reverse discharge from the surface of the latent image bearer to the charger. A pulse ON time of a voltage component toward a reverse discharge side relative to a desired surface potential Vde of the latent image bearer is shorter than a pulse ON time of a voltage component toward a normal discharge side relative to the desired surface potential Vde of the latent image bearer.