Writing was invented much later as was speech (Now believed to be about 100,000- 200,000 years ago). Thus what was man's first tool is open to debate. Fire is believe to have come under control of Man about 1-15 million years ago. The big question has been was fire the first invention or the hand Axe? While there are some researchers who believe hand axes were in use 2.5 million years ago (About 1 million years before the control of Fire) many other researchers question this.
The real debate is did proto man MAKE the hand Axe and kept it with him, or did proto man pick up any old rock chirped it to something he could use and than discard it when he no longer needed it? Even Today Chimpanzee have been seen "making tools" to perform a specific function than discarding that tool after the function has occurred.
Homo Erectus differently kept tools on him and made tools that he would need in the future. This is what I consider "tool usage" and appears about the same time as Home Erectus started to Control Fire. It is a debate, was the hand Axe man's first invention or was fire? We can debate this forever but given the lack of written records from the time period a debate without any resolution.
The tradition has been Fire was man's first tool and I am staying with that tradition until I see hard evidence against it. At the same time I am open to the comment that the Hand Axe may pre-date the control of Fire. Both require some thought of future usage, something you do NOT see in Chimpanzees.
For some comments on Early man, Fire and tools see:
http://kie.berkeley.edu/ned/data/E01-980521-006/full.htmlhttp://ms.cc.sunysb.edu/~wtucker/Homo_erectus.htmlhttp://www.stanford.edu/~harryg/protected/chp22.htmhttp://www.ecotao.com/holism/hu_habilis.htmhttp://donsmaps.com/erectus.htmlhttp://uts.cc.utexas.edu/~bramblet/ant301/fourteen.htmlhttp://www.accuracyingenesis.com/image.htmlSome sites related to Speech"
http://www.hypography.com/article.cfm?id=34162http://www.humanevolution.net/a/language.htmlhttp://partners.nytimes.com/books/first/l/lieberman-eve.html