Abstract: A mass spectrometer for performing a selected ion monitoring (SIM) measurement and/or multiple reaction monitoring (MRM) measurement on each of one or a plurality of target components contained in a sample under one or a plurality of measurement conditions is provided. The mass spectrometer includes: a storage section 41 in which SIM measurement conditions and/or MRM measurement conditions are previously stored for a plurality of components; a measurement condition selection receiver 43 for performing the following operations when a command to create a method file in which measurement conditions are described is issued by a user: reading the selected ion monitoring measurement conditions and/or multiple reaction monitoring measurement conditions of the plurality of components, displaying the measurement conditions on a screen, and receiving a selection by the user; and a method file creator 48 for creating a method file in which a measurement condition selected by the user is described.