Absolutely not. In the blunt words of Finnish historian Jason Lavery, "Finland faced a Soviet army larger than Finland's total population."

Things aren't quite as drastic when you consider the actual force deployments during the war. At the beginning of the war, the Finnish regular army numbered some 33,000 strong, from a population of around 4 million. The vast majority of Finland's manpower during the war came from several different reserve forces, including the Territorial Force, the Army Reserve, the Civil Guard, which brought Finland's total military strength to around 400,000 personnel. A further 100,000 women from the Woman's Auxilliary Army were available for support roles.

That is not to say that Finland had half a million combat-capable soldiers at their command, but even if they had, they would have paled in comparison to the full strength of the standing Red Army. Most generous estimates suggest Finland had fewer than 300,000 fighting men at their disposal, and most were very poorly equipped. Some did not even have weapons. Lavery concluded that Finnish forces were outnumbered by a minimum margin of 2 to 1.

The Soviet Union invaded Finland with 450,000 men, which was a small fraction of the total military manpower the USSR had available (which was in the millions). You'd have to play some absurd semantics games to say that Finnish infantry outnumbered their Soviet opponents at the beginning of the war. You'd have to count nearly every warm Finnish body as 'infantry' and then be very nit-picky about who in the Red Army was technically classified as infantry to make that claim, but that wouldn't be an argument in good faith.

Sources:

Philip Jowett, Brent Snodgrass, Raffaele Ruggeri. Finland at War: 1939–45, Osprey Publishing (2006) p. 17–18.

David Kirby. A Concise History of Finland, Cambridge University Press (2006) p. 208–211.

Jason Lavery. The History of Finland, Greenwood Press (2006), p. 117–120.