A successive approximation type A/D converter includes: a reference signal generating section generating a reference signal; a comparator comparing an analog signal input thereto with the reference signal and converting the analog signal into a digital signal; and a control section controlling the reference signal to perform oversampling by executing an A/D conversion process on the analog signal at the comparator plural times such that the analog signal is A/D-converted into a digital value of N bits at the first A/D conversion process and such that the second and subsequent A/D conversion processes are performed starting with a lower bit of the (N−n)-th or lower order with upper n bits of the N-bit digital value obtained at the first A/D conversion process fixed.