A silver halide emulsion sheet for detecting track of charged elementary particles, in which emulsion at least one silver halide emulsion layer and at least one hydrophilic protective colloid layer are applied on both surfaces of a transparent support, and a compound selected from benzotriazoles is contained in said at least one silver halide emulsion layer.A processing method for processing the above-described silver halide emulsion sheet with a developer comprising a developing agent represented by formula (A): wherein R1 represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. A developer for use in developing the above-described silver halide emulsion sheet, comprising a developing agent represented by the above-mentioned formula (A).