PURPOSE: To connect a micro ISO relay to an electric connection box provided with a receiving part for an ISO relay.

CONSTITUTION: A converting housing 7 of relay converting structure of mounting a micro ISO relay 2 to be connected to an ISO relay receiving part 6 and four sheets of converting bus bars 8 to 11 received in the converting housing 7 are provided in an electric connection box 5 provided with the ISO relay receiving part 6. A lower end of these bus bars 8 to 11 is connected to an internal circuit of the electric connection box through terminal inserting ports 6a to 6d of the ISO relay receiving part 6, also to connect an upper end of each bus bar 8 to 11 to each terminal of a micro ISO relay 1 mounted in an upper part of the converting housing.