We observed the glucose concentration of solutions using a near-field microwave microprobe (NFMM). Instead of the usual invasive technique, we take the advantage of the noncontact and noninvasive evaluation capabilities of an NFMM. The NFMM with a high Q dielectric resonator allows observation of small variations of the permittivity due to changes in the glucose concentration. By measuring the reflection coefficient we could observe the concentration of glucose with a detectable resolution to 0.5 mg/ml (0.05 %). The glucose biosensor using a NFMM provides an unique approach for glucose monitoring for diabetes.