To shorten the test time of a memory cell of a nonvolatile memory in a non-volatile memory and a microcomputer incorporating it.

In a non-volatile memory in which a memory is made a writing prohibition period until frequency output A1 of a timer counter counting clocks of an internal oscillation circuit 1 is outputted after applying a power source, in order to shorten a writing prohibition period, a switching circuit 7 is provided between the preceding stage part 2-1 of the timer counter 2 and the poststage part 2-2, in a test state, timing at which frequency-divided output A1 is outputted is shortened by applying a clock of the oscillation circuit to the poststage part 2-2.