A transistor-type protection device includes: a semiconductor substrate; a well of a first-conductivity-type formed in the semiconductor substrate; a source region of a second-conductivity-type formed in the well; a gate electrode formed on the well via a gate insulating film at one side of the source region; plural drain regions of a second-conductivity-type formed apart from each other and respectively separated at a predetermined distance from a well part immediately below the gate electrode film; and a resistive connection part connecting between the plural drain regions with a predetermined electric resistance.