1. An apparatus for detecting a blinking state, the apparatus comprising: a state-of-eye distinguishing means for calculating a feature value that represents a state of an eye, for an eye-area which has been detected by searching a frame image, based on pixel data of pixels that constitute the eye-area; a threshold value setting means for calculating a first threshold value representing the feature value at a first transition point from an open state to a closed state and a second threshold value representing the feature value at a second transition point from the closed state to the open state, based on the feature value calculated for a targeted eye when the targeted eye is open, and storing the calculated first threshold value and the calculated second threshold value in a memory; a blinking state detection means for detecting the blinking state of the eye corresponding to the eye-area, by sequentially comparing the feature values, which are sequentially calculated for a series of the frame images by the state-of-eye distinguishing means, with one of the first threshold value and the second threshold value, which have been stored in the memory by the threshold value setting means; and a timer which is configured to be set at a predetermined time, wherein said timer is started when a closed eye is detected, wherein the time of the timer is determined when an open eye is detected, and wherein the period of time from the closed eye detection to the open eye detection is compared with a predetermined time set by the timer to determine if the eye is blinking.