Provided is an electromagnetic switch device for starter in which an auxiliary relay is provided and which has a small size and can be easily manufactured. The electromagnetic switch device for starter includes: a main contact chamber forming a space in which a pair of main fixed contacts are located and a main movable contact can move; and a sub contact chamber forming a space in which a pair of sub fixed iron cores (A), (B) are located and a sub movable contact can move; and a cylindrical terminal block in which the main contact chamber and the sub coil are arranged so as to be adjacent to each other in the radial direction with a partition wall provided therebetween and separating the sub coil and the main contact chamber from each other.