A resonance element supported by a bearing structure includes a crystal chip and an excitation electrode. The crystal chip includes a main surface having a support surface portion being in contact with the bearing structure. The excitation electrode is disposed on the main surface, has an electrode area, and includes an electrode indentation boundary partly encompassing the support surface portion. The electrode indentation boundary has a first boundary end and a second boundary end being opposite to the first boundary end. The electrode indentation boundary and a reference line segment defined by the first and the second boundary ends form an electrode indentation region having an indentation area. A ratio of the indentation area to the electrode area ranges from 0.05 to 0.2.