As the diamond crystal, a diamond crystal in a bulk form including dislocation concentration regions is formed. An interval between each of the dislocation concentration regions is from 10 nm to 4000 nm. The crystal orientation of crystal main face at the surface of the diamond crystal is any one of (100), (111), or (110). An external shape of the diamond crystal in a surface direction is a rectangle, a circle, or a circle having an orientation flat plane. The rectangle is set to have a side length of not less than 8.0 mm. The circle is set to have a diameter of not less than 8.0 mm.