A position detection device for adjusting positions of a mold and a substrate using a mold mark formed on the mold and a substrate mark formed on the substrate includes a detection unit configured to detect light from the mold mark and the substrate mark, and a processing unit configured to obtain a positional relationship between the substrate and the mold based on a detection result of the detection unit, wherein the processing unit obtains the positional relationship between the substrate and the mold based on a corrected signal obtained by removing a noise component based on the light from the mold mark from a detected signal based on the light from the mold mark and the substrate mark.