The SAGA Light Source is a middle-scale synchrotron radiation facility, and the accelerator consists of a 255-MeV linac and a 1.4-GeV electron storage ring. Electron beams are injected into the storage ring through a 20-degree pulsed septum magnet at a repetition rate of 1 Hz. We have replaced the original in-vacuum pulsed septum magnet with a new out-of-vacuum pulsed magnet to improve the vacuum condition in the injection section and the injection efficiency. The peak leakage field on the bump orbit from the septum magnet is less than 1.5 mT at nominal excitation current of 3700 A. With the new septum magnet, an ultrahigh vacuum (10(-8) Pa) is maintained in the injection section with a stored current of 300 mA at the energy of 1.4-GeV.