An electrical steel sheet provided with an insulating coating is disclosed. A pre-treatment liquid to be used on an electrical steel sheet having a forsterite coating on a surface thereof before applying an insulating coating treatment liquid containing a phosphate is also disclosed. When a phosphate concentration of the pre-treatment liquid is defined as A mass % in terms of H3PO4, a refractive index R of the pre-treatment liquid satisfies Formula (1): 9.0×10−4×A+1.3340≤R   (1).