Provided is a pressure sensor apparatus including a lead frame, a pressure sensing element mounted on the lead frame to measure a relative pressure between a first part and a second part, and a housing including a reference medium inlet hole to apply a pressure of a reference medium to the first part, and including a target medium inlet hole to apply a pressure of a target medium to the second part, wherein the reference medium inlet hole is provided in a first surface of the housing, wherein the target medium inlet hole is provided in a second surface of the housing other than the first surface, and wherein the lead frame includes one or more insertion terminals configured to be inserted into and electrically connected to terminal holes of a wire connector.