Abstract: A crystal unit according to this disclosure includes an IT-cut round crystal element supported at two points on an outer periphery portion of the IT-cut round crystal element. A rotation angle in plane between a straight line connecting the two points and Z? axis of a double-rotation is within a specific range. The specific range includes an angle where an amount of frequency variation is zero.

Abstract: The metal base for a crystal unit includes: a base body in which at least a pair of through-holes are formed; a pair of leads provided with a supporter for supporting a crystal blank at the head thereof; and glass charged into the respective through-holes to electrically insulate the leads from the base body and hermetically seal the through-holes. A step is formed in a region of the lead corresponding to the outer bottom surface of the base body, the lead is made up of at least a first lead portion on the through-hole side from the step and a second lead portion in a direction in which the lead extends out from the step. The diameter of the lead of the second lead portion is smaller than the diameter of the lead of the first lead portion.