A diagnosis board is electrically connected with a test apparatus for testing a device-under-test and used in diagnosing the test apparatus. The test apparatus has a test head containing test modules for sending/receiving signals to/from the device-under-test. The diagnosis board has a plurality of sub-boards arranged substantially on the same plane, substantially forming a plane as a unit, and connected with each part of a plurality of terminals of the test modules and used for diagnosing the connected terminals, each of the plurality of sub-boards having a plate-like shape. The diagnosis board also has a fixing section for attaching and fixing the plurality of sub-boards in a body to the test head.