Provided is a pressure detection device including a pressure detection unit and a channel unit. The channel unit has a contact part arranged in contact with the pressure detection unit, the contact part has a protective film arranged in contact with a pressure detection surface and configured to block contact between the pressure detection surface and a liquid and a body forming an opening arranged at an end of the channel, the protective film and the body are formed of a thermoplastic fluorine resin, and the protective film is arranged so as to close the opening of the body and welded to the body in an annular region extending circumferentially about the axis.