In a lamp: an LED module and a circuit unit for lighting are housed within an envelope composed of a globe and a case; the LED module is attached to an end of an extension member that extends from a mount, which closes an opening at one end of the case, into the globe; the circuit unit is mounted inside the case; an insulation member disposed inside the case ensures insulation between the mount, which is made of metal, and the circuit unit; the insulation member has a bottomed cylinder portion inserted into the mount, and a protrusion portion formed on an outer circumference of the based cylinder portion that protrudes toward an inner surface of the mount; and the insulation member is attached to the mount by the protrusion portion pressing against the inner surface of the mount.