In a transistor including an oxide semiconductor film, movement of hydrogen and nitrogen to the oxide semiconductor film is suppressed. Further, in a semiconductor device using a transistor including an oxide semiconductor film, a change in electrical characteristics is suppressed and reliability is improved. A transistor including an oxide semiconductor film and a nitride insulating film provided over the transistor are included, and an amount of hydrogen molecules released from the nitride insulating film by thermal desorption spectroscopy is less than 5×1021 molecules/cm3, preferably less than or equal to 3×1021 molecules/cm3, more preferably less than or equal to 1×1021 molecules/cm3, and an amount of ammonia molecules released from the nitride insulating film by thermal desorption spectroscopy is less than 1×1022 molecules/cm3, preferably less than or equal to 5×1021 molecules/cm3, more preferably less than or equal to 1×1021 molecules/cm3.