Rice farmers in Japan are becoming increasingly interested in direct seeding technology as a way to save labor spent on seed raising and transplanting. This article explores the technology adoption mechanisms of direct seeding, as well as the effects of technology adoption on mixed farming, and farm scale. In estimating adoption mechanisms, attention was paid to both the farm's efficiency, measured by frontier cost function, and to the joint decisions relating to direct seeding and outsourcing. Multinomial probit estimates showed that a farm's efficiency and scale had significant and enormous impacts on the adoption decision, and that direct seeding adopters and outsourcing adopters had contrasting farm characteristics. These empirical results imply that demand for direct seeding must grow continuously if the increasing trend in farm size continues, that a farmer's ability or skill is the key to adoption, and that targeting must be effective when conducting technical guidance and consultation for direct seeding. Among the effects of direct seeding, little is known about how farmers utilize their saved time in further productive activities such as mixed farming or expanding the size of the farm. However, these effects were not found clearly from parametric models and propensity score matching. This result implies the need for further investigation on the way to utilize saved labor to fully realize the potential gain of direct seeding technology.