An embodiment electrical connection device for a vehicle includes a male connector housing having a blade terminal mounting portion, a female connector housing to couple to the male connector housing and having a tab terminal mounting portion, a blade terminal mounted in the blade terminal mounting portion, and a tab terminal mounted in the tab terminal mounting portion to connect to the blade terminal when the male connector housing and the female connector housing are coupled to each other. An embodiment blade terminal includes a terminal body having a first connection portion and a contact spring inserted into an inner side of the first connection portion to connect the terminal body and the tab terminal to each other by being brought into contact with the tab terminal when the tab terminal is inserted into the inner side of the first connection portion.