A disc discriminating method and an objective lens adopting the same, in which fast disc type discrimination and stable reproduction signal generation is performed. The method includes the steps of increasing and decreasing a focus voltage applied to an actuator of an objective lens facing a disc having an information-recorded plane to move the objective lens in a standby state at a neutral position to a focus position corresponding to the disc, detecting a movement distance value of the objectiveness from a focus signal applied to the actuator when the objective lens moves to the focus position, comparing the movement distance value with a reference value and determining the disc to be a thick disc if the movement distance value is greater than the reference value, and determining the disc to be a thin disc if the movement distance value is less than the reference value.