An electromagnetic switch includes a main contact housing portion housing a main contact mechanism having a pair of fixed contacts fixedly disposed maintaining a predetermined interval and a movable contact disposed to connect with and separate from the pair of fixed contacts in a contact housing case; an auxiliary contact housing portion housing at least two auxiliary contact mechanisms having fixed contacts and movable contacts disposed connecting to and separating from the fixed contacts; and an electromagnet unit having a movable plunger individually coupled to move the movable contact of the main contact mechanism and the movable contacts of the auxiliary contact mechanisms. The main contact housing portion, the auxiliary contact housing portion, and the electromagnet unit are disposed in series.