In a light emitting device, a substrate on which LEDs are arranged in line is used as a light source used for the sidelight of an illuminating apparatus serving as a backlight of sidelight type. The frame of the LED includes a first portion, a second portion, and a third portion. The second and third portions are arranged on both sides of the first portion. The length of the longest part of the first portion in a first direction d1 in which the LEDs are arranged is larger than the length of the longest part of each of the second portion and the third portion. Each of the second portion and the third portion has a part having a length in the first direction d1 shorter than the length al of the longest part of the first portion in the first direction d1. Each of the total length b1 of the part of the second portion in which an electrode is disposed and the electrode in the first direction d1 and the total length c1 of the part of the third portion in which the electrode is disposed and the electrode in the first direction d1 is shorter than the length a1.