Lamp life meter and endoscope light source unit

A lamp life meter adapted to be detachably coupled to a light source of the type which generates a lamp on signal indicating that a lamp of said light source is turned on, said lamp life meter detecting the total length of time that the lamp is turned on, said lamp life meter comprising:

• a housing having at least one contact terminal adapted to be coupled to one or more output terminals of said light source, said lamp on signal appearing on one or more of said output terminals;
• a clock generator located in said housing and generating clock signals;
• a counter located in said housing and counting said clock signals whenever said lamp or signal indicates that said lamp is on;
• and
• a display mounted in said housing for displaying an indication of the time said lamp has been turned on.