Resonator element, resonator, oscillator, and electronic device

A resonator element whose outer shape is formed by etching a Z plate which is cut at predetermined angles with respect to the mutually orthogonal X, Y, and Z axes which are the crystal axes of a quartz crystal, comprising:

• a base having a top part and a bottom part, the base having a notch located between the top and bottom parts, and the base having a base center line parallel to the Y axis;
• a resonating arm extending from the top part of the base in a first direction parallel to the Y axis and the resonating arm having an arm center line parallel to the base center line;
• and
• a supporter having a first part and a second part, the first part extending from the bottom of the base in a second direction parallel to the X axis, the second part continuously extending from the first part in the first direction, the second part being parallel to the resonating arm, and the supporter being in an L shape with a bent part, wherein
• an edge of the notch is provided between the base center line and an extension line of the arm center line, and
• a width of the resonating arm gradually increases toward the base along a third direction opposite to the first direction.