An LED lighting device comprises a first portion provided with a lamp cap, a second portion provided with a case and a power supply, a third portion provided with a heat exchange unit and a light emission unit connected and forming a thermal conduction path. The light emission unit and the power supply are electrically connected. The lamp cap extends in a first direction. The light emission unit comprises an illuminator and a substrate, wherein the substrate having a mounting portion provided with the illuminator, the mounting portion parallel to the first direction, wherein the distance b from the beginning of the second portion to the plane where the center of the LED lighting device is located satisfies the following formula: (L2+L3)/5