A semiconductor device includes a plurality of chips comprising a plurality of I/O terminals connected in common via through electrodes. Each of the chips includes an I/O compression circuit operable to output a compression result obtained by compression of data of a plurality of internal data buses to a first I/O terminal of the plurality of I/O terminals. Each of the chips also includes a test control circuit having a register group that sets the number of the first I/O terminal. Setting information that assigns different first I/O terminals to different chips is set in the register group. Each of the chips inputs or outputs data with use of the number of the I/O terminal that is different from those in other chips. Thus, the I/O compression circuits can concurrently perform an I/O compression test in parallel in the plurality of chips without a bus fight.