A picture image processing apparatus includes a candidate detection unit that detects a lateral boundary line candidate and a paint-blank boundary line candidate from the picture image information acquired, and a verification unit that verifies whether or not the lateral boundary line candidate etc. detected is the lateral boundary line etc.; a storage unit that memorizes, as hysteresis information, verification information including the lateral boundary line etc. in case the lateral boundary line candidate etc. detected has been verified to be a lateral boundary line etc. The storage unit also memorizes car speed information associated with the hysteresis information. The apparatus further includes an estimation unit that, using the hysteresis information and the car speed information, estimates positions of the lateral boundary line etc. in a next frame. The storage unit memorizes the estimation information including the position in the next frame of the lateral boundary line position etc. estimated. The verification unit uses the estimation information memorized at a time point of estimation in the storage unit to execute verification.