Lens unit

A lens unit comprising:

• a lens barrel with a through-hole;
• a first lens press-fitted into the through-hole;
• a first step catching an outer edge of the first lens in the through-hole;
• a second lens press-fitted into the through-hole in a direction of an optical axis of the first lens, the second lens having a diameter larger than that of the first lens;
• and
• a second step catching an outer edge of the second lens in the through-hole;
• wherein each of the first lens and the second lens contacts a portion of an inner wall of the lens barrel in the through-hole, said portion being substantially in parallel with the optical axis, while applying contacting stress to the inner wall so as to be held by the portion of the inner wall of the lens barrel;
• wherein a sloped area of the inner wall of the lens barrel in the through-hole from the first lens to the second lens is further provided between the first step and the second step, the sloped area having an upper end and a lower end,
• wherein the upper end of the sloped area conforms to an end of the second step and the lower end of the sloped area conforms to an end of the first step, and
• wherein a diameter of the inner wall in the sloped area continuously changes between the first step and the second step and at least one of the upper end and the lower end of the sloped area is curved.