A mounting detection circuit of a printing apparatus outputs a first mounting inspection signal to one of first terminals and outputs a second mounting inspection signal to one of second terminals thereby performing a mounting inspection for determining whether or not printing materials are mounted depending on whether or not second mounting response signal is received, and examines at least one of whether or not the second mounting response signal is influenced by the first mounting inspection signal and whether or not a first mounting response signal is influenced by the second mounting inspection signal thereby performing a leakage inspection for determining whether or not there is a leakage between the first and second terminals.