An ionizer 1 detachably attached to a main body 2 of an ion analyzing device includes an ionization section 10 including a sample stage 14 and light irradiation units 11, 12, and 13 configured to irradiate a sample placed on the sample stage 14 with light, a base body, and a movably-holding mechanism which is provided on the base body and configured to hold the ionization section in a manner movable or rotatable about one or more axes.