A scanner includes an image capturing module, a drive roller assembly, an idle roller assembly, and a guiding structure. The image capturing module is for capturing an image of an object. The drive roller assembly is for driving the object to move along a feeding direction. The idle roller assembly is for preventing a moving direction of the object away from the feeding direction by resiliently pressing the object. A feeding passage is formed between the drive roller assembly and the idle roller assembly. The guiding structure is disposed in front of the feeding passage and for guiding a normal direction of a leading edge of the object to be oblique relative to the feeding direction at an oblique angle. Therefore, the present invention can effectively reduce variation of a resistance force acting on the object as the object moves in the feeding path, which prevents image distortion.