Provided is an optical filter having a light-transmitting region of transmitting light having a predetermined wavelength and a light-blocking region disposed adjacent to the light-transmitting region to block out the light, wherein the light-blocking region has an optical density gradation relative to light in the normal direction, from the contact point to the light-transmitting region along an in-plane direction, and the optical density is the smallest at the contact point to the light-transmitting region.