The perception and production boundaries between a fricative [s] and an affricate [ts] in Japanese were investigated to clarify the relationship between them. Regression and discriminant analyses revealed that the perception and production boundaries between [s] and [ts] were represented by very similar linear functions defined by the variables of rise duration and steady+ decay duration. In addition, the perception boundary discriminated between [s] and [ts] in the production data with a small error rate (7.11%). These results indicate a correspondence between the perception and production boundaries separating [s] and [ts], and suggest a close connection between speech perception and production.