A flash tube reflector able to distribute light of the flash tube evenly is disclosed. The reflector is a vertical portion of an elliptic cylinder extending along an Y-axis. A cross section of the reflector along the XY plane is a portion of an ellipse. A zenith E at the reflector intersects the X-axis. The flash tube contacts the reflector at E. A is a center of the flash tube and c is a distance between E and A. F1 is a first focus of the ellipse of the reflector and f1 is a distance between E and F1. F2 is a second focus of the ellipse and f2 is a distance between E and F2. The relations of c, f1, and f2 are 0.20 ≦c/f1≦0.45 and 0.14≦f1/f2≦1.0.