According to one embodiment, an illumination device includes a light guide having a first plane, a second plane, a side plane, a first tilted plane, and a second tilted plane, an angle formed between the side plane and the first tilted plane and an angle formed between the side plane and the second tilted plane being acute angles, a first semiconductor laser element including a first light emitting part, and a second semiconductor laser element including a second light emitting part. The first light emitting part is opposed to a first intersection part of the side plane and the first tilted plane, and the second light emitting part is opposed to a second intersection part of the side plane and the second tilted plane.