To prevent a staff from forgetting pulling out the key of a lock device for locking a control board case.

A board unit 10 for a game machine is provided with: a control board case 11 for storing a main control board; a case body 12 for storing the control board case 11 and a plurality of control boards; a lock device 13 having a keyhole 13a and locking the control board case 11 so as not to be removed from the case body 12; and a cover body 15 attached to the case body 12 so as to be openable/closable. The cover body 15 includes a barrier 15a which is formed at a position opposing the keyhole 13a in a state where the cover body 15 is closed. The height of the barrier 15a from the case body 12 in the closed state is lower than the height from the case body 12 to the top of the key 14 in a state where the key 14 for locking/unlocking the lock device 13 is inserted into the keyhole 13a.