An electrical junction box comprising: a circuit board; and a board connector including a housing holding a connection terminal and fixed to the circuit board, wherein the circuit board includes a slit provided in a linear end, and a plurality of penetration holes provided at positions different from a through hole to which the connection terminal is soldered, and arranged parallel to the end with the slit therebetween, the housing includes a positioning surface in abutment with the end of the circuit board, a positioning rib formed projecting from the positioning surface in a perpendicular direction perpendicular to the positioning surface, and inserted into the slit to come into contact with the circuit board at least in a width direction of the slit in an abutment state in which the end of the circuit board is in abutment with the positioning surface, a support portion formed corresponding to each of the penetration holes, formed projecting from the positioning surface and extending toward the circuit board, and coming into abutment with a first surface of the circuit board in the abutment state to support the circuit board, and a projecting portion formed projecting from the support portion toward the circuit board, and inserted through each of the penetration holes, the projecting portion includes a plurality of divided pieces (20A-20C) circumferentially divided by a plurality of slits extending toward an axis from an outer peripheral surface so as to be formed individually elastically deformable in a radial direction, a regulation portion formed projecting radially outward from the outer peripheral surface and regulating movement in an insertion and removal direction of the circuit board between the regulation portion and the support portion in an insertion state in which the projecting portion is inserted through the penetration hole is formed in at least one of the divided pieces (20A-20C), the connection terminal comes into an insertion state through the through hole of the circuit board in an insertion state in which the positioning rib is inserted into the slit, and in a state in which the projecting portion is inserted through the penetration hole to regulate the movement of the circuit board by the regulation portion, and the board connector is fixed to the circuit board by soldering the connection terminal to the through hole. a circuit board; and a board connector including a housing holding a connection terminal and fixed to the circuit board, wherein the circuit board includes a slit provided in a linear end, and a plurality of penetration holes provided at positions different from a through hole to which the connection terminal is soldered, and arranged parallel to the end with the slit therebetween, a slit provided in a linear end, and a plurality of penetration holes provided at positions different from a through hole to which the connection terminal is soldered, and arranged parallel to the end with the slit therebetween, the housing includes a positioning surface in abutment with the end of the circuit board, a positioning rib formed projecting from the positioning surface in a perpendicular direction perpendicular to the positioning surface, and inserted into the slit to come into contact with the circuit board at least in a width direction of the slit in an abutment state in which the end of the circuit board is in abutment with the positioning surface, a support portion formed corresponding to each of the penetration holes, formed projecting from the positioning surface and extending toward the circuit board, and coming into abutment with a first surface of the circuit board in the abutment state to support the circuit board, and a projecting portion formed projecting from the support portion toward the circuit board, and inserted through each of the penetration holes, the projecting portion includes a plurality of divided pieces (20A-20C) circumferentially divided by a plurality of slits extending toward an axis from an outer peripheral surface so as to be formed individually elastically deformable in a radial direction, a regulation portion formed projecting radially outward from the outer peripheral surface and regulating movement in an insertion and removal direction of the circuit board between the regulation portion and the support portion in an insertion state in which the projecting portion is inserted through the penetration hole is formed in at least one of the divided pieces (20A-20C), the connection terminal comes into an insertion state through the through hole of the circuit board in an insertion state in which the positioning rib is inserted into the slit, and in a state in which the projecting portion is inserted through the penetration hole to regulate the movement of the circuit board by the regulation portion, and the board connector is fixed to the circuit board by soldering the connection terminal to the through hole.