Recently, consumer's demand for natural preservatives is increasing because of residual toxicity, mutagenicity and etc. of synthetic preservatives and the study of natural preservatives is being done. In this study, antimicrobial activity of spices was investigated Fungi occurred in bread and a noodle without mustard after 3days and 4days, respectively. However, they didn't occur in bread and noodle with mustard ball. Temperature of the water used in mixing-up mustard powder didn't affect antimicrobial activity of mustard. Fungi occurred in bread with cinnamon, Japanese pepper or horseradish after 4days, 4days or 6days, respectively. However, there wasn't the occurrence of fungi in bread with mustard after 8days, yet. Mustard and horseradish of extracts by water of spices had a strong antimicrobial activity. But the extracts by ethanol had low antimicrobial activity.