An assisting focusing method is applicable in an image capture device having an auto focusing (AF) procedure. The AF procedure has a preset sampling interval. The assisting focusing method includes the following steps. An image for focusing is captured. A face parameter of a face block in the image for focusing is calculated. According to the face parameter, a parameter-to-focus conversion table is looked up to acquire a focusing section. According to the focusing section and a face sampling interval, the AF procedure is performed to acquire a target focus. The face sampling interval is smaller than the preset sampling interval.