Electric junction box and power supply device having the same

A downsized electric junction box and a power supply device having the same are provided. The electric junction box includes: a box main body including a connector engagement portion to be engaged with a connector and relay mount portions for mounting relays; and a wiring unit received in the box main body including mount portions mounted on a bottom wall of a lower case of the box main body and a plurality of terminal portions positioned inside the connector engagement portion and extending from the mount portions. A terminal positioning portion of the lower case includes a planar wall positioning the terminal portions on a surface thereof, extending walls extending from between the adjacent terminal portions, and parallely-projecting walls each projecting from an end of the extending wall in parallel with the planar wall. The mount portion includes a cutout portion through which the parallely-projecting wall is passed.