An object of the present invention is to provide a means for measuring amylase activity existing in biological samples such as saliva in a more convenient manner and is particularly to provide a means (reagent for measurement, method for measurement and apparatus) by which a sample containing high concentrations of amylase is measured. There has been found a means (reagent for measurement, method for measurement and apparatus), whereby amylase activity in an amylase sample having a high activity value can be quite conveniently measured by making an oligosaccharide substrate carry on a support in an enzymatic method for measuring amylase activity using a modified oligosacharide substrate, whereupon the present invention has been achieved.