To realize image recognition of high precision while suppressing a memory capacity to be used.

A specific pattern detection device is provided with a binarization processing part which binarizes image data of an input image, a first storage part in which binarized image data is stored, a flag generation part which specifies a plurality of pixels in binarized image data and generates a flag indicating whether a prescribed pixel exists within a range prescribed by these pixels or not, a second storage part in which the flag is stored, a detection part which divides the image of binarized image data stored in the first storage part into a plurality of blocks and detects a graphic pattern approximating a specific pattern by each block, a decision processing part which decides similarity between the graphic pattern detected by the detection part and the specific pattern on the basis of the flag stored in the second storage part, and a pattern matching part which subjects the graphic pattern detected by the detection part to detailed image recognition processing in accordance with the decided similarity.