A What your photo shows is a "Garrucha." It is an inexpensive handgun much favored in tough, impoverished South American areas generally, although my own experience with the type was in Brazil. On several visits to the north east part of that country, I saw such arms in marketplace stalls during the mid-1970s.
Originally introduced before World War I, I understand that Belgium and Spain were then sources for many of these inexpensive small arms. That war interrupted supplies, however, and local manufacture seems to have begun in the 1920s or 1930s.
Have you examined your pistol for proofmarks? There is no commercial proofhouse in Brazil. Calibers originally favored were rimmed 7.65 mm/.320 center-fire and 9 mm/.380 center-fire cartridges for revolvers, but Metalurgica Municoes Amadeo Rossi y Cia (of San Leopoldo, Rio Grande do Sul, Brazil) introduced a .22 rimfire version in the early 1970s, and later upgraded its punch. Whether proofmarked or not, do not fire that pistol!-A.W.F. TAYLERSON