1. An in-vehicle running-environment recognition apparatus, comprising: an input unit for inputting an image signal transmitted from an in-vehicle imaging device for photographing external environment of a vehicle; an image processing unit for detecting a first image area by processing the image signal inputted via the input unit, the first image area having a factor which prevents recognition of the external environment of the vehicle; a to-be-processed image determination unit for determining that an environment recognition processing is possible in a case that a size and a position of the first image area in the inputted image signal by the image processing unit are less than predetermined threshold values, and determining a second image area based on the size and position of the first image area; and an environment recognition unit for recognizing the external environment of the vehicle based on the second image area determined by the to-be-processed image determination unit.