A multi-bus semiconductor device and a method of its probing test perform the DC test for individual pads of a device while dealing with an adequate number of devices for simultaneous measurement based on the scheme of input/output pad number compressive test. The semiconductor device includes switch elements SW0-SW4 connected between input/output pads P0-P4 and a testing line L0 so that pads in an arbitrary combination, among the off-probe pads P1-P4 that are not made in contact with the tester probe Pr0, are selected for testing in correspondence to the combination of switch elements that are turned on. The input/output buffers of the pads under test are deactivated to block their internal current paths. The corresponding switch elements are turned on to connect the off-probe pads under test to the probe pad P0 that is made in contact with the tester probe Pr0, and the leak current of the probes is measured with the tester TS.