The present invention provides a watermark information embedding device, a watermark information processing system, a watermark information embedding method and program that can provide a two-dimensional code enabling detection of copying. The watermark information embedding device comprises a first wavelet transform unit (12), a watermark information embedding unit (14) and an inverse wavelet transform unit (150). The first wavelet transform unit (12) performs a discrete wavelet transform on an original image of a two-dimensional code and decomposes this into various frequency components, namely an LL component, an LH component, an HL component and an HH component. The watermark information embedding unit (14) embeds the watermark information in the HH component as a high-frequency component in an oblique direction. The inverse wavelet transform unit (150) recomposes the two-dimensional code by performing an inverse discrete wavelet transform on the HH component in which the watermark information is embedded, and on each of the frequency components namely the LL component, the LH component and the HL component.