To improve maintenance performance of a battery apparatus module of a battery pack, as well as to reduce in size and weight and reduce cost of a battery apparatus module containing a service plug.

In the battery apparatus module 3, since a current sensor 61 and a battery ECU 62 are mounted on a service plug 4 in addition to a power fuse 50, a signal harness for connecting both 61 and 62 becomes unnecessary. Then, the current sensor 61 and the battery ECU 62 are fitted in compact so as ESD countermeasure components to be unnecessary, and there is no signal harness so as to enable to save a space for managing it, thus reduction in size and weight as well as cost reduction can be attained. Moreover, specification of failure parts can be carried out quickly, the current sensor 61 and the battery ECU 62 can be easily inspected or exchanged so as to improve maintenance performance.