Did the early humans first build fire during the stone age or the bronze age?

The Stone Age is generally considered to be the period between about 450,000 years ago and about 2,300 years ago, when humans first began to work with metals (the Bronze Age). The earliest evidence we have of hominids regularly using fire is from about 1.6 million years ago, although presumably, the migration of hominids from the warmth of the African continent into areas of Asia and Europe necessitated the use of fire for heating. Based on current evidence, anatomically modern humans appear to have been around for only the last 150-200,000 years. Since the ancestors of modern humans regularly used fire for various purposes, there are a couple of answers to your question:

1) Before the stone age

2) It depends on what you mean by "humans"