Variations of energetic electrons released from the Jovian magnetosphere are investigated in detail by using data from three spacecraft, Pioneer 10, 11, and Ulysses. Analyses with the three spacecraft data confirmed that the Jovian electrons are modulated by the dynamic pressure of the solar wind at the position of Jupiter. It is also found that the release rate of energetic electrons is controlled by the polarity of IMF having dawn-dusk or latitudinal dependence. The enhancements of released electron flux were detected during the toward polarity of IMF when the spacecraft were located in the upstream or dawn side of Jupiter. On the other hand, Ulysses detected enhancement in away polarity of IMF when the spacecraft was on the duskside of southern hemisphere. We made a simulation to reproduce the electron variation of Jovian electrons observed by Pioneer 11 considering the convective and diffusive transport in the interplanetary medium. According to the simulation, the observed enhancements of electron flux originating from Jupiter are well represented by the coupling of both the source modulation at the Jovian magnetosphere and the transport effect in the interplanetary medium.