A control unit having a press-fit structure, comprising a connector assembly body and a substrate (2,4) assembled to each other, the connector assembly body including: a terminal; and a press-fit terminal formed at a tip end of the terminal, the substrate (2,4) including: a connected portion to which the press-fit terminal is connected; and a guide portion (20,21) extending from the substrate (2,4) around the connected portion, the press-fit terminal including: a tip end portion; a contact portion which is adjacent to the tip end portion, and is to be connected to the connected portion; and a first enlarged portion formed on the terminal side of the contact portion the guide portion including: an opening portion opening in a direction in which the press-fit terminal is positioned; a guide hole extending from the opening portion to the substrate (2,4); a tapered surface, which is formed on an inner side of the opening portion, and has an inner dimension decreasing as separating away from the opening portion; and a reduced-hole portion formed continuous to the tapered surface, the tip end portion (10A, 11A) of the press-fit terminal being configured such that the contact portion is positioned with respect to the connected portion while the first enlarged portion is guided by the tapered surface and an inner wall of the reduced-hole portion, wherein the press-fit terminal includes a reduced portion having a width smaller than a width of the first enlarged portion, wherein the reduced portion is formed between the first enlarged portion and the terminal, wherein the contact portion comprises an elastic leg portion having a hole passing through in a direction perpendicular to a longitudinal direction of the press-fit terminal between the tip end portion and the first enlarged portion, wherein the connected portion comprises an insertion hole formed in the substrate and coated with a conductive member, wherein the connector assembly body is connected to the substrate when the elastic leg portion is inserted into the insertion hole and at least a portion of the elastic leg portion is brought into contact with the conductive member of the insertion hole, wherein the press-fit terminal includes a second enlarged portion formed on the terminal side of the reduced portion, wherein the guide portion includes an enlarged-hole portion formed on the substrate side of the reduced-hole portion, wherein the first enlarged portion and the second enlargedportion are guided by the inner wall of the reduced-hole portion to be inserted into the guide portion, wherein, when the first enlarged portion is positioned at the reduced-hole portion, the tip end portion is positioned in the insertion hole, and wherein the press-fit terminal is configured such that the elastic leg portion is positioned in the insertion hole when the second enlarged portion is positioned at the reduced-hole portion. a terminal; and a press-fit terminal formed at a tip end of the terminal, a connected portion to which the press-fit terminal is connected; and a guide portion (20,21) extending from the substrate (2,4) around the connected portion, the press-fit terminal including: a tip end portion; a contact portion which is adjacent to the tip end portion, and is to be connected to the connected portion; and a first enlarged portion formed on the terminal side of the contact portion a tip end portion; a contact portion which is adjacent to the tip end portion, and is to be connected to the connected portion; and a first enlarged portion formed on the terminal side of the contact portion the guide portion including: an opening portion opening in a direction in which the press-fit terminal is positioned; a guide hole extending from the opening portion to the substrate (2,4); a tapered surface, which is formed on an inner side of the opening portion, and has an inner dimension decreasing as separating away from the opening portion; and a reduced-hole portion formed continuous to the tapered surface, an opening portion opening in a direction in which the press-fit terminal is positioned; a guide hole extending from the opening portion to the substrate (2,4); a tapered surface, which is formed on an inner side of the opening portion, and has an inner dimension decreasing as separating away from the opening portion; and a reduced-hole portion formed continuous to the tapered surface, the tip end portion (10A, 11A) of the press-fit terminal being configured such that the contact portion is positioned with respect to the connected portion while the first enlarged portion is guided by the tapered surface and an inner wall of the reduced-hole portion,