The literature on students' attitudinal constructs in science education asserts that students hold dichotomous attitudes toward science (AS). For instance, studies from the Relevance of Science Education project reveal that students possess negative attitudes in terms of their favourableness toward school science, preference toward scientific careers, and emotional states toward science (negative "intrinsic" AS), despite their positive perception that science is important for society (positive "extrinsic" AS). The issue demands in-depth examination, since not enough science educators have studied the effects of the dichotomous AS on science education. Rather, they have attempted to improve the uncategorised AS for stimulating student achievement in science education. Hence, the aim of this study is to clarify how the dichotomous attitude (intrinsic AS and extrinsic AS) relates to the two educational products in science: interest inventory and conceptual understanding. One hundred and sixteen physics learners in Japan were sampled for fitting the structural equation model in this study. Our final model validated by "LISREL" suggests that intrinsic AS exclusively stimulate students' interest and conceptual understanding in physics, while extrinsic AS fail to play their expected role. Finally, features of the sampled 10th-graders and their dichotomous AS are further interpreted with the prevalent concept of the hidden curriculum. (Contains 3 figures and 5 tables.)