That looks an awful lot like the O-scope end of a Tektronix probe, probably a 10X. The box part probably contains a compensation network and adjusting trimmer.
It should work with your Hitachi, but be sure to set the probe's compensation trimmer according to the scope's manual.
FWIW: I've never been keen on anyone but Tektronix for O-scopes. Had I been shopping around, I would have made my bench 'all blue' as it were.
Happy tweaking.