According to one embodiment, a method for manufacturing a pressure sensing device includes preparing a sensor unit and a mounting substrate. The sensor unit includes: a membrane body; and an element unit provided on the membrane body. The element unit includes: a first electrode; a second electrode; and a first magnetic layer provided between the first electrode and the second electrode and having magnetization in a first direction. The mounting substrate includes: a base; a first electrode pad provided on the base; and a second electrode pad provided on the base and provided apart from the first electrode pad. The method further includes joining the first electrode pad to the first electrode while heated, and joining the second electrode pad to the second electrode while heated, with an external magnetic field along the first direction applied to the sensor unit.