An interlayer film for laminated glass, having a one-layer structure or a two or more-layer structure, containing a thermoplastic resin, the thermoplastic resin containing a polyvinyl butyral resin, and containing at least a magnesium salt and a potassium salt, wherein a portion on a first surface of the interlayer film is measured for Ratio 0 of Ion Intensity of Potassium/Ion Intensity of Thermoplastic Resin with the use of TOF-SIMS, and a sputtering and measurement process in which the first surface portion measured for Ratio 0 is subjected to sputtering one time and measured for Ratio of Ion Intensity of Potassium/Ion Intensity of Thermoplastic Resin with the use of TOF-SIMS is performed n times, and n Ratio n s of Ion Intensity of Potassium/Ion Intensity of Thermoplastic Resin obtained from the first to n-th sputtering and measurement processes are collected to calculate an average value 1 ≤ n ≤ 10 of 10 values of Ratio 1 ≤ n ≤ 10 measured within a range of 1 ≤ n ≤ 10 and an average value 1 ≤ n ≤ 150 of 150 values of Ratio 1 ≤ n ≤ 150 measured within a range of 1 ≤ n ≤ 150, the Ion Intensities of Potassium and Ion Intensities of Thermoplastic Resin each being measured according to the method in the description, the average value 1 ≤ n ≤ 10 is more than 1.1 times the average value 1 ≤ n ≤ 150, and wherein, in the case of an interlayer film with the one-layer structure, the content of magnesium in the interlayer film is 50 ppm or less and the content of potassium in the interlayer film is 300 ppm or less, and in the case of an interlayer film with the two or more-layer structure, a surface layer positioned at the first surface side contains magnesium and the content of magnesium in the surface layer positioned at the first surface side is 50 ppm or less, and the content of potassium in the surface layer positioned at the first surface side is 300 ppm or less. containing a thermoplastic resin, the thermoplastic resin containing a polyvinyl butyral resin, and containing at least a magnesium salt and a potassium salt, wherein a portion on a first surface of the interlayer film is measured for Ratio 0 of Ion Intensity of Potassium/Ion Intensity of Thermoplastic Resin with the use of TOF-SIMS, and a sputtering and measurement process in which the first surface portion measured for Ratio 0 is subjected to sputtering one time and measured for Ratio of Ion Intensity of Potassium/Ion Intensity of Thermoplastic Resin with the use of TOF-SIMS is performed n times, and n Ratio n s of Ion Intensity of Potassium/Ion Intensity of Thermoplastic Resin obtained from the first to n-th sputtering and measurement processes are collected to calculate an average value 1 ≤ n ≤ 10 of 10 values of Ratio 1 ≤ n ≤ 10 measured within a range of 1 ≤ n ≤ 10 and an average value 1 ≤ n ≤ 150 of 150 values of Ratio 1 ≤ n ≤ 150 measured within a range of 1 ≤ n ≤ 150, the Ion Intensities of Potassium and Ion Intensities of Thermoplastic Resin each being measured according to the method in the description, the average value 1 ≤ n ≤ 10 is more than 1.1 times the average value 1 ≤ n ≤ 150, and wherein, in the case of an interlayer film with the one-layer structure, the content of magnesium in the interlayer film is 50 ppm or less and the content of potassium in the interlayer film is 300 ppm or less, and in the case of an interlayer film with the two or more-layer structure, a surface layer positioned at the first surface side contains magnesium and the content of magnesium in the surface layer positioned at the first surface side is 50 ppm or less, and