To provide a ball game partition facilitating the installation and the movement and supporting a mark line to supports with a falling-down structure.

A support retainer 5 is attractedly fixed on a board 4 mounted on an installation surface by being magnetically attracted by a permanent magnet 6, and the base part of the support 2 supporting a net body 3 is retained to the support retainer 5. The adjoining supports 2 and 2 of the game ball partitions 1 installed in a line are supported to a common board 4 so as to connect the adjoining interval.