Abstract: The present invention relates to a test strip using formaldehyde or peroxide, which are sarcosine metabolites, for diagnosing prostate cancer, and a method for diagnosing prostate cancer by means of the test strip, the present invention allowing a simpler and more rapid diagnosis of prostate cancer than the conventional methods, such as using a spectrophotometer, and with respect to qualifying and quantifying sarcosine in urine, the test strip is reacted in a test urine sample, as with a conventional urinalysis test strip, so as to allow the color change to be visually checked, thereby allowing prostate cancer to be diagnosed without professional personnel and expensive equipment.