Ionizer

An ionizer disposed in an ionization chamber separated from an analysis chamber by a partition provided with an ion introduction port, the ionizer comprising:

• an ion introduction tube provided in the partition, an inlet of the ion introduction tube being the ion introduction port;
• a heating member provided in the partition and configured to heat the ion introduction tube;
• an electrospray ionization probe configured to charge and nebulize a liquid sample as charged droplets, the electrospray ionization probe being disposed such that a nebulization axis is orthogonal to a central axis of the ion introduction port;
• and
• a heated gas supply mechanism configured to blow a heated gas, from a predetermined direction, to a position between a tip of the electrospray ionization probe and an intersection point of the nebulization axis and the central axis, the position being separated from the tip by a predetermined distance or more,
• wherein the predetermined direction and the predetermined distance are set such that the heated gas does not reach the electrospray ionization probe, and
• wherein the heated gas supply mechanism is arranged such that a central axis of a blowing direction of the heated gas passes through the heating member without passing through a portion of the ion introduction tube exposed to the ionization chamber.